He is not a good QB. He has missed more deep, and open, WRs this year than he has hit. He has done enough to manage games and makes some plays with his feet but he misses a lot of looks.
I respectfully disagree, depending on how you define "good". He's not a great QB in that he's not likely to win too many games with his arm. At least not yet. But I'm starting to think that he's not an awful QB either.
I don't recall Gio missing a ton of wide open deep passes. Actually, I can't recall many times he's been asked to throw deep balls. Bolin missed a bunch of deep, open WRs earlier in the season, and missed them worse than Gio has missed on his pretty rare deep-ball attempts. Is it possible you're conflating the two QBs?
There appear to be some footwork and vision problems he needs to work on. He has failed to recognize or be in a position to throw to a couple receivers breaking open downfield. Maybe that's what you were talking about? In some cases, it was because Gio was caught rolling left, so throwing further to his left required him to stop, pivot and throw. He actually fell down trying to do that in one recent game - I think the open receiver was Blackshear, but not sure.
But in general, I think Gio is actually throwing the ball better and better. His apparent arm strength in the last game was actually kind of impressive to me. I suspect that, if provided with WRs that quickly and constantly got separation, Gio'd look better as a passer.
He's making plays with his feet (when healthy), not taking a lot of sacks even against some stout defenses, putting throws where nobody but a receiver can catch them (mostly) and hasn't been turning the ball over. His screen pass to Edwards was actually a pretty difficult play to make and he not only made it but hit Edwards in stride, certainly a big part of why that pass wound up being a TD pass.
For me, the jury is still out about Gio. I'd rate him a pretty good game manager QB at the moment, with potential to be a better than average college QB if we can get receivers that regularly get open, and that fight successfully for the ball.