He may be more of a goal scorer, but he has no problem creating assists either. Along with his 102 goals he also has 37 assists. For a striker that scores that many goals it is freakin' insane that he still produces the goods for other people to put the ball in the back of the net.
It's not that he can't assist, as you say.
It's more considering what his focus is and then wondering who he should be paired with.
I'm not going to say Aguero and Matri couldn't work, but I don't think it would get the best out of either of them, while Sanchez and Matri would suit each other pretty well I'd imagine.
I'd like to see Aguero playing with Quaglierella, because he moves well and could link up with Aguero, where Matri doesn't move about as much or link up so well.
So, I can't see how the "theory he can't lead an attack" is even plausible. That theory, statistically, is shot to hell.
Depends what you mean by leading the attack.
Leading the attack to me is more about style of play than quality.
I'd say, for instance, that in a Iaquinta-Del Piero pairing, Iaquinta is leading the line because he would be the focal point.
Del Piero, of course, would still be the main man, though.