Vlad - I don’t like when people play him as a tank, I’ve seen it work where people rush FoN and then Warmogs but it seems like a waste to me.
Nunu - I think he’s a good jungler and can gank pretty good. My only problem is that after his ult he doesn’t do much, as his slow seems to have such an epically long cool down.
Udyr - The more I play him the more I think he does best built with Wriggles and then a bunch of tank items and Trinity Force. I love his spammable stun and his ability to take out carries and neutralize certain ults (Kat, WW for example). Only thing I don’t like is he has to jungle and gank to be really effective.
Gragas - I don’t play him much, his ult was more useful when clump up AoE reigned supreme. I’d probably play him as a beefy caster (Zhonya, Abyssal, RoA) instead of a straight tank if possible.
Singed - Trolololol. I’m not good with him so I don’t play him but a well played Singed is an absolute nightmare. Still like Gragas I think he’s best with a bit more AP than pure defense.
Garen - He was designed to be melee dps instead of a tank and only became one really when people started sunfire stacking. Silences are nice against caster heavy teams but less useful in other situations.
Cho’Gath - Naturally high hp, a high damage ult that can help neutralize carries and two other CC moves (albeit one that is a skill shot). Even without AP he’s an unholy terror. I see nerfs in his future.
Alistar - His Q is good CC but has a really long cool down, his W can neutralize a carry if used properly (which isn’t easy). He’s awfully squishy naturally though and extremely slow. I love to play him more as a support/offtank. With some support type items, a sheen and a little survivability he becomes a force.
Galio - Totally a situational pick these days. His lane presence and farming got knocked down which is probably why he doesn’t get picked as much because his AoE ult is still good. If you face a lot of casters or you have a team that can take advantage of the ult then he can still do quite well.
Nasus - Same thing as Alistar, shines more when built with some amount of damage and a little survivability. Doesn’t have the hard CC to be useful as a pure tank.
Maoki - haven’t played him yet. Haven’t seen enough of him to be sure.
Mordekaiser - Has 0 CC hard or soft which but does still do respectable damage when itemized purely as a tank. When played well he can stand in the middle of fights for a long time harassing and dealing out damage. Still if your team is lacking in CC and your tank is Mord, I feel like you’re setting yourself up for failure.
Warwick - After listening to McKnight’s insisting I’ve been going just he first part of Madreds and then entirely tanky after (usually SV, Banshees and Randuins) and noticing that I do in fact stay alive a lot longer. You probably won’t be one shotting as many carries this way, but in team fights you’ll do better and if you coordinate with your team and suppress the other teams carry while they focus the carry then things can go quite nicely.
I think that about covers it, I suppose I could discuss things like Tankrelia or Tanklaf but those kinds are really gimmicky.