i'm assuming you're going to mention skarner, who is a great jungler.
or udyr or lee sin or shaco or trundle or dr mundo or volibear or jax or maokai or nocturne or rammus or shyvana or jarvan or nautilus or malphite or amumu or alistar or cho gath or xin zhao or olaf or tryndamere
any of those really
i'm a bit burnt out on him at the moment, because it seems every game i play with him, i do really well, but we still lose. his lack of close-the-cap (beyond just going fast) means that it's hard to get that first hit, and beacuse he has no hard cc until level six, he's not good ganking at mid unless the other player's up at your tower because they'll just flash out. he has a high damage output and can do a lot, and his slow and general utility make him a lot of fun to play
this is all true, and he's still
a much better jungler than warwick
now, ww suffers from a lot of the same issues - but ww can solo dragon at level five or six, whereas i rarely solo dragon ever with skarner.
the gold gain from soloing dragon early is negligible compared to the gold gain any other jungler can earn their team by successfully ganking before level six
ww also doesn't really need blue, whereas skarner kind of needs it
this is true, but if the only issue was mana, one questions why you wouldn't take udyr or lee sin or trundle or cho gath
i know skarner's one of the top junglers in the game, but there's a reason people aren't seeing him as much anymore
it's because he's no longer super easy mode; champ popularity will always be determined by how powerful a champ is compared to how easy they are to play as
i've always felt that junglers need some sort of hard cc to get early kills against smart opponents, and more and more that's what i'm seeing.
ganks are arguably not about getting the kill so much as it is forcing someone out of lane
skarner for instance can gank pre-six because his Q and his W still give him good chasing power and damage; even if he or his teammates fail to kill anyone, they'll still probably force them out of lane
characters like xin, shaco (fear), rammus, and jax are becoming more and more used because of their high early-game damage output and their hard cc, and honestly, i'd take hard cc over light cc and more damage against a good teamcomp.
you have to consider how worth it it is to have that early game hard cc, though - having jax' stun for an early gank is better than an early slow from skarner, but then you're losing out on skarner's ult which is one of the best hard ccs in the game (definitely the best utility wise of the four supressions)