He's good with Yasuo on top and Katarina mid (especially at the same time), but without anyone to complement his ult, he's nothing special. Missed your Q on gank - no gank. He's the lowest picked jungler at the moment I think.
Nah, he's good with any champs. It's true aoe type champs like Kat are awesome with him, but any champs benefit from his abilities. I've had a lot of games where good opposing players honored me after the game saying they couldn't do anything to our carries because I kept them constantly cc'ed with Amumu's abilities. Obviously if your team is terrible, and when you go in and cc the entire enemy team, they don't do anything (which happens quite a bit), Amumu won't help, but you know, in that case, no champ will help you win, unless you are a smurf.
Also, that miss Q thing, Q is on a several second cooldown. Miss your Q, go back in the jungle, double back and try again. Unlike say WW, who if he fails to get a kill on his ult has to wait a minute.
The beautiful thing about Amumu is that if you build him tanky, say Cinderhulk Jungle item, followed by some tanky boots, Sunfire Cape, Deadman Plate, Banshee's Veil, and Liandri's, you now have 4000+ health, 200+ armor, 120+ MR, and still do (roughly) (4% of enemy health per second + 24 magic damage from W) + (1-2 % from liandri's passive) + (31 I think from sunfire) + (30 or so from cinderhulk), so that's like (being too lazy to do actual math) roughly maybe 7% of enemy health per second just by standing in the middle of their team to ALL enemies. So in 10 seconds, you'll take 70% of their squishies health just by standing next to them, and maybe half that for tankier champs. Throw in your AOE e on a short cd, your high damage ult, your q, and you are doing deceptively high damage despite being a tank.
Also, I wouldn't go champ popularity. Like most statistics it means very little. Before his remake, Viktor used to be the least played champion in LoL. I mained him in the mid back in those days, and completely wrecked people with him. I think I recall other people here having the same experience.
About Malzahar, I agree, he is a paper tiger champ. Looks great on paper, 4 high damage abilities with high scaling, some cc, but in practice, very underwhelming. It's very hard to get his abilities to work with each other in the middle of the chaos of battle. And if he messes up his abilities, which is very likely, he has no mobility, escapes, or tankiness, so he instantly becomes fodder for champs like xin, yi, etc. Maybe a very high skill player can get him to amazing places, but for us mere mortals, there are much better champs out there.
