I think Brooks has gone from overrated to a bit underrated. His flaws are well known, but there is a place for 6'5" SGs with long arms that can score and create their own shot. He has serious defensive potential with that kind of length as well.
I think his ceiling is an above-average starter, floor is 10th man gunner, and with a little player development could be a solid rotation guy. It all depends on:
1) Playing above-average defense (which he has all the tools for)
2) Maturing as a player, i.e. becoming coachable
Both reachable goals, and considering he almost wasn't in this trade I'll take it.