McInnes has been 'serviceable' in his performances so far. While he hasn't really put a foot wrong (thankfully, in part, due to referees missing a few forward passes here or there), McInnes hasn't done anything eye catching either. For this reason, I believe it is hyperbole to say he is a discernible upgrade in Rein. As some others have pointed out, McInnes hasn't made many breaks out of dummy half, and his lack of dash in this area makes Rein look like The Flash.
As for his defensive qualities, he is a workaholic, but so was Ben Ellis back in the day (for those with good memories).
My critique of McInnes does acknowledge a couple of redeeming features though. He seemingly can endure long playing minutes, and he has good vision as evidence by his crafty kick for Aitken's first try against Cronulla on the weekend.
If this were a report card, I'd be awarding a C+ with room for improvement.