Wow, these comments are idiotic. I shouldn't be surprised.
Kazakusan is emblematic of the "printing a neutral that is actually just for one class" problem. OP is correct. Getting Kazakusan, an expensive endgame card, out on the board when your opponent has anywhere between half to a third of the mana you do is the problem.
Ramp druids are still able to have 2 turns worth of mana in one go for the entire game, with or without kazakusan.