Lately I been seeing him just dominate, even among the tank junglers. I hardly see them build "tank" anymore, they just stack HP and AP then walk in and bomb, soloing other tanks at their leisure and then get so fed they hop on any other character solo and eat them.
Amumu was always good, people just forgot about him because he wasn't FotM for a while. Cinderhulk absolutely helps get him going. Good Amumu's can carry, that's why he was banned the majority of S3
The meta always adjusts to compensate. If Amumu gets more popular, I predict champs like Nunu, Udyr and Shaco will also rise up in popularity since they can bully him out of his jungle early on. I don't think that Amumu's too strong, he's just not really being dealt with right; tanks and supports need to put an emphasis on hitting him with randuins and other cc to keep him off of your back line.
