I don't have high expectations for Hill either. Frankly I think he gets cut or maybe traded for a conditional late round pick on the off chance someone likes him (Gabbert fetched a 6th, so who knows). I agree with your analysis of him 100%. Really the only reason he's got a shot to be on the roster at this point is the dearth of outside receivers.
And on Powell, I think there's a good chance he makes the roster. But if Richardson outplays him in TC, gets a bigger role on specials, and shows well in pass pro I could see him getting the nod for a roster spot over Powell. Maybe they choose to carry four backs though.