Well the dire avengers were only ok. Now this was expected, but still disappointing. Although their volume of fire was really nice verse the 90 brimstones... Caused a lot of morale testing on those 30 mans.
I would also say the troupe master. Only reroll to wound not to hit like most characters did very little. I know it can be good but often if they were something big I was worried about I just cast doom on them or shot them with fusion pistols.
The harle troupes. Man they were killing demon princes, slaying whole units of brimstones. Really sick with soulburst. I will say that the smite verse them was sick. He killed a whole unit with 1 smite. Ouch
I was really digging all the "fly" abilities and the tactical advantages of moving about. I want to stick with the speed.
I definitely think the lack of "numbers" was an issue. Sometimes I would have a serpent holding an objective and 2 heralds would jump over and take it away. That was frustrating for sure. Hard though in elder to get mass number since their infantry can be weaker.
Well let's start with the top:
For 97pts you can get 10x Guardians w/ Shuriken HWP, or for 105pts you can get 10x Guardians w/ Brightlance HWP. In cover they've got the same save as the Dire Avengers in the open. They've actually got more firepower when you factor in the HWP, yes at a slightly shorter range on their basic guns, but with a HWP their range and threat factor far out weighs that of the Dire Avengers.
The Troupe Master. I understand your frustration there. I guess I've never thought about it much, I haven't really used his ability to reroll failed to wounds to replace Doom, but to rather allow me to cast Doom on a different target(One I'm planning on shooting instead of assaulting with the Harlequins). Also, I would defintely give the Troupe Master a Fusion Pistol and Harlequin's Embrace. With his 2+ to hit in shooting and assault, it's almost insane not to utilize these weapons on him.
Smite vs. Harlequins = Bad News. In this edition they are the ultimate glass hammer. I really don't know what you could do to counter this except try and make sure they're not the closest unit to a Psyker.
Things with the "Fly" rule. Speed and maneuverability have always been things the Eldar rely upon to win games. To this I will add that since you are running Ynarri, try to stick with things that will benefit from SfD, ie. Infantry and Jetbikes.
I'm not all that familiar with the Dark Eldar so I'll stick with what I know, Craftworld. I haven't playtested Swooping Hawks this edition, so no input on these guys.
However, I can testify that Warp Spiders are still one of the fastest units in the game. They will almost always be able to get to where you need them and I have never had a problem getting them in range to use their guns. When they use their WJG they gain the "Fly" rule. Their guns have also got a similar rule to the Shuriken Weapons with the exception that when they roll a 6 to wound it's -4
AP. When they appear from across the board next to an enemy unit and dump basically 20 rending shots into them, I've had several opponents take notice. If they can wipe out the unit and are within 7" you can then Soulburst and move them out of danger. This has gotten a couple of
WTF?
I don't own any of the Harlequin Jetbikes(Although I'd like to get a unit of 6) and I haven't used the Craftworld Jetbikes much either, but when I have they performed well. I will also say there is absolutely no reason to ever take the Twin Shuriken Catapults over the Shuriken Cannon. The Cannon is only 2 points more per model and doubles the range and increases the strength by two at the cost of one shot. This is a no brainer.
Numbers. With the exception of inexpensive Guardian Squads(This is subjective to what you are comparing them to of course) most everything in the Eldar list is at a premium price. You will, most likely, always be outnumbered and you're going to have to eliminate enough of your opponents forces to make your numbers count for something.
GW has done a great job of returning Eldar to the finesse army that they were for many years. I'm very happy with the changes that they've made so far.
The Eldar lost a great deal of their appeal to me in the last edition when everybody just ran Scatbike Spam and Wraithknights for the win. In fact, I put my Eldar away for almost a year and played my Space Wolves(I refuse to use
TWC) exclusively, just because I didn't wan't to get lumped in with all of the bandwagon jumpers. Now that we're back to thinking, back to being the army that can hit like a brick, but falls apart when the wind blows south. I've broken out the pointy eared Space Elves and am enjoying the challenges they present once again.
~Ice~ 
