Well, when you hire someone you look really hard at his track record. You also interview him, talk to him, check out his background, etc. I think that has been done. You then hire who you think is the best candidate. I think that has probably been done. I don't know who else they could have hired with better credentials. Or, you can disregard these things and go with your "gut" feelings. Which one is going to win the majority of the time?
You can what if him to death. But, that's all it is, a what if. Yeah, I'm concerned about his height, about his small hands, but, has that affected him in the past? Has he fumbled more than others, had passes knocked down or been intercepted exceptionally more, or been hurt?
He's played against the best all thru his past and has done quite well from what I have read. Why can't he succeed at this next level? He was the best in the other levels, so, you want to go with someone lesser than him, who has not been as successful?
Right now, your only complaints are, "yeah, but " or "what if's". And that points to anybody.