Assuming Drew Brees actually returns to the field this year...and I'm not entirely sure that happens, even though the dude wanted to play with 11 broken ribs...

But assuming Drew Brees comes back, we won't know this year. Too small a sample size.

Now assuming Drew Brees retires next year, and Hill has done enough to be given the reigns... We probably know about four or five games in to next season.

Teams will have had an entire off-season to dissect any possible weaknesses and put those into play. If he plays well then, we know. If teams figure out something... Which is a bit hard to do because of his sheer athleticism... But if teams figure out something, that will show up.