Your points are 10 off for your Wolf Lord by the way. He's 220 without any wolves.

At 1500 points, 3 5 man squads is workable. Its not my personal preference, but there isn't anything particularly risk in doing it. That said, Power Fists are a waste of points on a model with only one Attack in its profile, especially for the cost listed in the Codex.

That one model costs 40 points to provide you with 1 close combat attack (not counting charges) at Initiative 1. Why is this bad? For 43 points you can instead get a Wolf Guard with Power Fist and Combi-Weapon to attach to the pack. The extra leadership makes a bigger difference than you think, and he has two attacks on his profile. Bringing a combi-weapon, he allows for two special weapons in a Razorback squad or for you to retain two special weapons in a Rhino based squad. For 3 points more. Its just a better use of your points all around.

Even better, why are you taking a Power Fist? Can Meltabombs serve you instead? I find you don't need every squad to have a Power Fist or Thunder Hammer. Roughly one for every two squads seems to work out just fine, since your units are supporting each other. You can save even more points by taking Meltabombs and Mark of the Wulfen/Power Weapons on the Wolf Guard pack leaders instead. Doubly so if you are running Lone Wolves at all.

AV11 is decent light armor, but its not invincible and with only 3 targets for enemy Anti-Tank you will find it won't last more than a few turns against most lists. Which means your troops are going to be out of the transport before end of game and exposed to enemy fire. This is why I don't like taking all Razorbacks and prefer to mix in a few Rhinos so you have some more numbers on your side.

Aside from that though, you have no ranged punch outside of your 3 Razorbacks. When they are gone, so is a significant part of your firepower. Even worse, you have a total of 3 guns that aren't even twin linked for your ranged suppressing fire. You don't need a bunch of guns for blowing up tanks. You need a bunch of guns for getting a 1-2 or a 5-6 (maybe a 3 depending on the enemy vehicle) on the damage table. You need to neutralize the enemy artillery for a turn or two for your troops and cavalry to close in. That's it.

This is why you see Rhinos with Living Lightning toting Rune Priests and so many "all missile launcher" Long Fangs.

Your Terminator squad is also lacking. It has no transport, so I assume you run it behind or in front of your Thunderwolf cavalry and all of that behind your 3 Razorbacks. Lending even more importance (and lack of other targets) for the enemy to be blowing those transports away. Wolf Guard are one of three places you can bring heavy weapons in on an Infantry platform with the Space Wolves. Your other two options are Wolf Scouts and Long Fangs. You have picked a Heavy Flamer.

I'll admit, Heavy Flamers are cool. But the Assault Cannon is a better choice despite the point cost (which wouldn't be a problem if you weren't bringing Power Fists on Grey Hunters!). In your list a CML makes even more sense, though I personally still prefer the Assault Cannon as its more effective against heavy infantry and AV14 thanks to Rending.

Also, Wolf Guard allow for wound allocation shenanigans, while aside from being surprisingly powerful is also actually fluffy for Space Wolves (each Wolf Guard fights with weapons of their personal preference). I'm not sure how you have it split up, but you have only 2 to 3 with unique wargear, and 3 to 2 with the same. None of it is particularly scary outside of Arjac.

Further, another strength of Wolf Guard is that you can mix armor types. This allows you to shave off 5 points a model (that's the wargear price difference by the way, 5 points) by taking Power Armor. All these little points add up and it allows you to throw some of these guys in with the Grey Hunter packs if you so wanted.

So this is why I think your 1500 list is okay. I see room for improvement personally. I'm sure that most of the time it plays well enough, but it could be more effective and have an easier time against certain match ups, without sacrificing anything important.

2500 points is going to see an awful lot more of the "goodies" in a Codex than 1500 points. This goes for your enemy more than you, since you are already taking your "goodies" (e.g. special characters and terminators; everything else is less a toy and more a utility in the Space Wolf list). What this means is you can expect to be facing some scary assault units, outflankers, and some deadly firepower. You are going to need to bring the same to be able to compete.

Luckily, you already got "scary assault unit" down. Keep the Thunderwolves. Consider bumping them to 3 plus the Wolf Lord. If the points are there when other necessities are covered you could take two units of two and give them each a Wolf Lord/WGBL to lead them. But you generally only need the one.

So you need some "outflankers", or more precisely: force projection. Deep Strikers/Fast Movers or Outflankers. So you have 3 choices: Wolf Scouts, a handful of units in Drop Pods (make sure its an odd number to capitalize on Turn 1) or Land Speeders. Please note, relying solely on one unit for this is not good. While that can work with Assault units, it doesn't with this. You need a few.

So what are you bringing? Njal is a good add, even without Terminator armor. Mind you, many of his powers do nothing if he can't see the enemy (and he can't in a Land Raider or Razorback), but he's still an excellent choice and a Space Wolf list without a Rune Priest just is missing something vital these days.

A Land Raider Redeemer for your Terminators. Not a horrible option, and its a strange list to some at 2000 points if it doesn't have a Land Raider. Personally I'm partial to Crusaders, but I see the appeal of the Redeemer easy enough. At the same time though, your Terminators themselves are giving you nothing major and you can free up 600 points almost by just dropping them and the Land Raider.

A suicide drop pod dreadnought. 140 points for a one shot Multi-Melta. Why not just spend half the points on a Land Speeder Tornado with multi-melta and heavy flamer? It does the same job and its not eating up an important force organisation slot and will probably live just as long.

So, what do you need?

More troops for one. At 1750, most Space Wolf lists out number you 2:1 for bodies, most of which are scoring. Most 1500 point Space Wolf lists have more ranged firepower, and almost all 1250+ point Space Wolf lists have more force projection. Roughly 600 points gets you 3 more scoring units in Rhinos with enough numbers to worry an opponent.

Wolf Scouts would be an excellent investment as well. As simple as 5 with a Meltagun to go Outflank (and they can bring any Wolf Guard pack leader in power armor or any HQ with Saga of the Hunter as well) or maybe a larger pack kitted out for both assaulting backline units and taking out tanks. 85 points minimum and 205 points maximum. All of it useful, and surprisingly disruptive to your opponent.

Roughly 300 points minimum of Long Fangs would do you as well. You don't have to do the all Missile Launcher thing that everyone raves about, though it is a bargain. Two of my three Long Fang packs run 3 HB and 2 LC and I never have yet have felt that the Heavy Bolters are "wasted". Mind you, that costs more than the Missile Launcher option point wise (by 15 points). Its also slightly less effective against AV11-12 while being more effective against AV10 and AV14.

Even better, give the Long Fangs TLLC Razorbacks. Even more anti-armor and they don't have to walk on the table in Dawn of War.

Don't want all Long Fangs? Your Land Raider isn't a bad option, but would be better if filled to the brim with Blood Claws. A pair of Vindicators or a Whirlwind, while not the best options, aren't entirely useless and can give you some firepower to make up for your fewer number of troops.

Really, your core is your Grey Hunters. You should have 4 of them in 1750/1850, and probably should have 5 or 6 troops at 2000/2500. Maybe one Blood Claw pack, if you are okay with them being easier to hit (and thus taking more wounds than Grey Hunters) in close combat. Everything else in the list should be build around supporting them in doing their job which is A) take and hold objectives and B) destroy the enemy. Anything that doesn't help that should be left home.

1500 Point List
Headquarters
Rune Priest 110
1 w/ Chooser of the Slain, Living Lightning, Storm Caller

Wolf Guard Battle Leader 115
1 w/ Combi-Melta, Wolf Claw, Meltabombs

Elite
Wolf Guard 124
2 w/ Combi-Melta, Power Fist
1 w/ Combi-Melta, Power Weapon, Meltabombs

Wolf Scouts 100
5 w/ x1 Meltagun, x1 Mark of the Wulfen

Troops
Grey Hunters 165
5 w/ x1 Meltagun, x1 Wolf Standard
Razorback w/ Lascannon and TL Plasma Gun

Grey Hunters 200
8 w/ x1 Meltagun, x1 Power Weapon, x1 Mark of the Wulfen, x1 Wolf Standard
Rhino

Grey Hunters 200
8 w/ x1 Meltagun, x1 Power Weapon, x1 Mark of the Wulfen, x1 Wolf Standard
Rhino

Fast Attack
Thunderwolf Cavalry 275
2 w/ x3 Storm Shield, x1 Thunder Hammer, x1 Meltabomb

Heavy Support
Long Fang 230
3 w/ Heavy Bolter
2 w/ Lascannon
Razorback w/ TLLC

Total 1499/1500

Notes
Slap the Rune Priest/WGBL and Power Fist Wolf Guard in the Rhino and the Power Weapon Wolf Guard in the Wolf Scouts (or the Razorback, but better with the Scouts). Rune Priest can throw Storm Caller up and give anything within 6" of the Rhino a 5+ cover save (in case you are in the open or for your Razorbacks) or he can open up the top hatch and fire Living Lightning at some enemy light-medium armor.

Please note, most people will tell you double Rune Priest. It usually is the "smarte"r move. At the same time, their 24" nullification zone doesn't stack and while double Living Lightning is nice, its usually not strictly needed. Especially at 1500 points.

Long Fangs obviously set up in cover and lay down suppressing fire at enemy tanks while firing Heavy Bolters at light armor (AV10/11) or infantry, almost always preferring the latter. I set them up for the more expensive point wise version I think is still effective, but if you want to build all Missile Launchers go for it.

Long Fang Alternative: Bring two Vindicators. This will probably be more effective at this point level, but if you are building this list to 2500 you have to consider the Long fangs will be more useful then than two Vindicators.

Your Thunderwolves do what you possibly already were doing, follow the Rhino/Razorbacks, using them as cover, and hit the enemy hard. I still think they are bloated point wise though I realize I use mine differently than other players. In contrast though, my pair of Thunderwolves cost 120 points to your 190. The downside is I don't have Storm Shields, which isn't a big deal against most enemies. I stay away from the ones it is a big deal.

250 Point Bolt On #1
Wolf Guard 43
1 w/ Combi-Melta, Power Fist

Grey Hunters 200
8 w/ x1 Meltagun, x1 Power Weapon, x1 Mark of the Wulfen, x1 Wolf Standard
Rhino

Notes
Brings you to 1750 with another scoring unit. You really will start to suffer at 1750+ with less than 4 scoring units. Expect one to die outright and the rest to be bloodied by the end. Leaves you 7 points left over, but not much you can do with them.

250 Point Bolt On #2
Wolf Lord 250
1 w/ Thunderwolf Mount, Frost Blade, Runic Armor, Fenrisian Wolf x2, Wolf Tail Talisman, Wolf Tooth Necklace, Belt of Russ

Notes
I left him pretty much alone for you, just gave him a Wolf Tooth Necklace. I think a person's Wolf Lord should reflect what they like. If you wanted to be more power gamey, it makes more sense to give him a Thunder Hammer and Saga of the Bear with a Storm Shield and leave the Thunderhammers off the normal Thunderwolves. Saga of the Warrior Born wouldn't be amiss with a Frost Blade, but your Wolf Lord would cost 265-280 points then which is a bit absurd. He's expensive enough already.

500 Point Bolt On
Wolf Guard[b] - 53
1 w/ TDA, Heavy Flamer, Chainfist

[b]Grey Hunters - 190
10 w/ x2 Flamer, x1 Power Weapon, x1 Mark of the Wulfen, x1 Wolf Standard

Land Raider Redeemer - 255
1/ Multi-Melta, Extra Armor

Notes
2 points only to spare. At 2500 points you will already have 4 other Wolf Guard so you can just take the heavy weapon one. Put him with a full squad of Grey Hunters and toss them in a Redeemer. Again, I'm assuming the Heavy Flamer is already built, otherwise I would suggest an Assault Cannon or CML. At the same time though there is something delightfully absurd about 5 flame templates at AP3, AP4, and AP5 just exploding everywhere.