Hey mate! check out www.da-warpath.com ! edit: I remember talking a lot of
40k ork tactics with you on dakkadakka and I sure as crap know you're too smart a git to ragequit on the good green-kind!
O&G fantasy forums that you may find more help from! (plus tons of great blogs and inspiration, tactics, etc!)
As far as blowing your wizards up, don't 6 dice spells, and that won't happen!

but in all seriousness, I throw 6 dice at foot in clutch moments as much as the next guy, but I try to max 4 dice spells to minimize my chances of miscasting (the 4 dice limit i impose on myself include magic mushroom die from night goblin shamans, so 3 + 1 mushroom)... I will 5-6 dice 20+ to cast spells from a wizard hat, because that's about the only way to make it go off.
Misfiring warmachines you can't really help with. That's just the luck of the roll. I've had games where I blew up both doom divers on turn 1, and blew my rock lobber up by turn 3. I've also had games where I managed to roll 18 direct hits in a row! just bad luck you're experiencing, wait a while and you'll have some good luck games with artillery dice to balance your bad ones out.
Why did your 10 deep units of goblins flee? if they have 10 ranks they should probably be steadfast unless you're fighting a bigger block of goblins, or skaven slaves, zombies or something. If they aren't going to be steadfast, they have 0 reason to be in combat. Goblins are "tarpits" they just get a killy-hammer unit like chaos knights, stuck in combat with them, so you can then flank charge them with your own hard hitting unit (like chariots, SOBUs, squigs, trolls etc)
If they were steadfast and fled still, what
LD were they using? If LD5 of the normal night goblins, than thats why! O&G are highly dependent on having your generals inspiring presence provide a substantially higher
LD value to units within 12" of him... (and by adding characters with higher
LD to units that will be outside his 12" bubble)
you can cut down squabbling by placing units more than 6" apart. Only units of 5+ more models within 6" are valid targets to be drawn into a squabble. if YOu HAVE to deploy them cloesly, put units with no casters in them slightly closer together than then units with casters. As the animosity rule states that the closest unit and their own fight.. So the only chance your shaman bunker will squabble is if they roll a 1 on the animosity roll themselves (as opposed to having a chance of being drawin into a fight by a nearby unit who failed animosity and rolled a 1 on the chart)
as far as failing charges, you are M4! you're average roll of 7 will make you have a average charge range of 11" with goblins. I would't shoot for long charges with these guys.
I don't really use black orcs so I can't speak much about them. You could of very well had a bad matchup with them, in which case its to be expected they will lose. However if you use them in conjuction with a night goblin unit charging, you now can net the opposing unit with -1S, making it that much harder to land wounds on your T4 black orcs.
Savage bigguns are very popular, especially with a L4 shaman with lucky shrunken head, and sometimes fencers blades.
Trolls are very popular for doing the same work black orcs do.
I don't use either of those though I specifically only play the goblin side of things...
That being said.... what works from the goblin side of the book?
NIght goblin blocks with nets = great tarpits, -1S in
CC to 1 unit on a 2+
Mangler squigs = tons of damage and will draw lots of fire, take 2. In fact, make 2 save 130 bucks. Couple ping pong balls and some putty, bam,
snotling pump wagons = awesome.
2D6 random movement (no charge reactions allowed) can upgrade to s5 impact hits (
2d6 not
d6!) and can updgrade to ignore armor saves.. they are immune to psyc... and you can have 4 in a normal size army! Plus you can fit 4 of them, 2 manglers, and plenty of artillery still!!
They will provide 4 targets, so quite a bit of saturation and redundancy going on, along with 2 manglers gives your opponents 6 oh gak units they want to kill. allowing your bigger, more point heavy, killy units, like savage orc bigguns a breather while crossing the board, and taking fewer casualties.
Squig herds, 2 WS4 S5 attacks at I3 a piece, Just expensive $$ wise. Trolls are probably better in long run.
doom divers are awesome, the
D6 redirect is great. if your opponent is silly and positions 2 blocks within 30mm of one another, place template between both blocks (touching both with the 30mm template) and do
d6 hits to both units... (only usefuly if your opponent places blocks 1" apart or slight more as the 30mm base is barely larger than a 25mm (1") gap.
fanatics inside night goblin units are good. especially if you shoot them through another unit that is being charge in front of them, so that the charger runs into them taking double damage... Your goblins will easily shrug off
3D6 hits, while chaos knights will cower at 6D6 of those same hits when they run into them..
sorry if this is longwinded, and again, check out da-warpath.com it really is a great repository for O&G info.