Good point.
I'd also point out that a passing offense is really only as good as the QB's ability to read the defense and get through his progression without advertising his intent. I'm overseas and only saw bits and pieces this season -- mostly listened on UConn+ -- but from what I did see, Roberson has room for improvement in seeing the field: reading the defense; looking to receivers, even when he has no intention of throwing to them, in order to sell the defense; and finding the second or third option when that man is open instead of the check down to the RB.
I have a feeling that many of the ticky tacky throws we saw and complained about were intended to be longer plays and Roberson either didn't have an open man or, and I saw this a fair amount, he's not up to game speed and couldn't find his best option.
That's really not on Charlton, as unhappy as I was with him. I didn't like what I saw, but I genuinely do trust a former NFL coach who instantly improved us to make the right call over my armchair, Monday QBing.