1) Pit of shades. Devestating overall, but placed over the slann you don't really can do anything if it get cast. My mate plays darkelves and thus run lore of shadow with this wizard, but he never has the sence to place it out of range from my Becalming Cogination so it's never a big deal. But anyone with two braincells to rubb together would place it well and beyond 24" of the slann and bring it down.
Scatter dice, miscasts, Becalming Cogitation denying IF casts, not being in range for several turns, 'Speed of Light' making it only work on 6's for the 'dodge' test...lot of things can go wrong with that one. At least with 'Purple Sun', you can IF it out of 'Becalming' range, and its RIP. And even then, if you don't IF (which usually involves burning a lot of power dice anyway), it can be dispelled.
It's a good power (I use Shadow myself), but Slann have some of the best magical defenses in the game, and they can buff their bunker to be awesome.
2) Crush the templeguard. Gets more difficult depending if the slann is running life or not. Nonetheless, templeguards are good but they are not too much to brag about in close combat if they get to face a bunch of black orcs or chosen or something. And after them gone the slann will be eaten alive.
Assuming you can get to the TG bunker at all, when the Slann is unmaking reality around you with his insane magic ability. Even if you do avoid the nukes and hexes and make it into combat, he can always just buff them to be faster, make them hit at S8, or regenerate them back to life (depending on Lore selection). I'd honestly try and flank charge TG first, to deny ranks and shift attention, then try for a one-two knockout with that Deathstar or elite assault unit you were sending in. I'd also try and snipe out the Slann first with Death magic or something similiar, because while he lives, he can cast (even whilst the bunker is dying in close-combat).
3) Pray for a miscst and hope that Cupped hand fails. Don't relay on this.
Hellheart is pretty annoying, as it burns out 'Cupped Hands' early. There are other magical gear I'm pretty sure that can cause Miscasts or snipe Wizards. Depends on the army.
The life slann army isn't all that bad to beat. It is definitely a change in tactics and thinking.
If you're not going to wipe a unit off the board so he can't bring it back at all in one round, don't focus on a single unit. He can only bring 1 unit back to life a turn since he can't cast the resurrection spell multiple times.
So take 5 off one unit, 5 off another unit, 5 off another unit. He can heal 5, not 15 (or whatever the cap is).
That way, when the 3 blocks of 10 get to the other side (instead 3 blocks of 20) you're already winning in static combat res and can hurt him in CC before he strikes back with his abysmal initiative.
Though that DOES require a fairly shooty army, it's worked for me in the past with both my empire, high elves and skaven. I imagine dwarves and dark elves could do the same thing.
Yeah pretty spot on. People forget that its not like Vampire Counts, he gets one rez cast every turn, and it's probably going into his bunker. He also needs 'Throne' for the other abilities to get better, so if you dispel that, he's much easier to deal with.
VC can still be pretty insane, they're just less power-dice spammy than before.
thats just not fun. 
