To be fair to Calloway, defenses had an easy job last year against us. He was our best receiver and he is only average at best. Put your best cover guy or two on him and he will not be super effective.
I think next season he should be in a more favorable position. The thing I like about him the most is how he fights for the ball on tough catches. I am not saying he is MT, but he has a little bit of that "it's MY ball" mentality.
If he looks overwhelmed again next year then perhaps he won't be the player we all want him to be. I think the best is yet to come.
I also think Harty is a gamer, though. He needs as many snaps as he can get.