What you're really saying is "it was stronger before, so the PCs will suffer for it being weaker now." This may be true, but that's totally independent of whether it is control or not. Also, damage/death is not control. To say that it is is silly. You can argue it is BETTER than control, but that itself is not clear. If I as a controller reshape the battlefield such that my side wins and wins more easily than some striker that might theoretically be in my place then obviously my control was superior. This IME is often the case. Time and time again I've seen wizards drive the enemy out of an otherwise unassailable position, delay the arrival of a monster in an effective combat position by multiple rounds, etc. Not to even mention things like just tossing a BBEG off a bridge into a bottomless pit with Spectral Ram (yeah, flying BBEG, so what, it was knocked prone...). It may SEEM like damage is the best thing there is in the whole world, but quite often you'd just rather force the enemy to be HERE instead of THERE.
Here is the problem. You talk about death isn't control but it actually is. Death is dealt in different ways but it's all done with damage. What you are saying is that essentially the Wizard needs to do more controlling at the expense of anything else. "Sure I could have killed that goblin over there, but I fulfilled my role better by shuffling him around the board some and enabled him to be killed next round by the rogue".
I'm sorry but it's more about defeating the enemy than fulfilling the role. No teamwork is lost with the original Wizard and he does his controller job just fine.