He's 6'2", only 5cm shorter than Buffon. That's not an NBA-style height recording either, if you see him in a team photo next to Gatti and Thuram you can see he is that height. He's a bit hunched. I also don't think Perin looks his height.
I agree that he's not convincing aerially aroud his box. I don't think he's that sort of keeper, but also, the chopping and changing around our defence never helps keepers in that regard.