My definition of tank is someone designed to tank hits, but not do 1 zillion damage trying to get "aggro". This pretty much means cc. However, Mundo at least (Volibear is debatable, but Riot gives him the tank tag, so I threw him in) was designed to be a huge jackass and tank all the damage.
Maokai is definitely still a godtier jungler, and anybody who thinks otherwise is being stupid. Point-and-click ganking (His W. The nearest comparison I can draw is like a low cooldown low damage Noc R) is just that great. It wouldn't make him godlike alone, but his E's usefulness in control over the entire map is undeniable. Mao's R is just godmode. -20% damage..... What can I say?
My bad on Amumu, he was permabanned last season and I was thinking the he still was for some reason. Either way, Mumu has R, and that's all he really needs. I've seen games won with a single well placed R on his part.
Galio's problem is that all of the 'good' tanks can fit onto any team. Unless you have one of a few specific champions that he synergizes really well with, there are always better choices, and you don't build a team around a tank so Galio has a really hard time finding a place to shine.
I really want to see what s3 changes too. Until then, we have a mess of useless tanks and a mess of crazy good tanks.
What I put for bait should've been Naut, fuckin autocorrect.
Ninja: I wouldn't consider Taric a tank especially, at least, not any more than any support gets by the end of the game with pretty much every support item having 300 or so hp each. If any supports were to count, it would be Nunu who might as well have a taunt on his R, and gets naturally tanky.