Wade wouldn't make the Thunder better at all. He's already declining as a player and would only make a noticeable positive impact in the right situation.
However, on a team that will struggle to shoot a good percentage from 3pt, with 3 ball dominant players including a PG who struggles to shoot the 3 who needs the ball to be most effective, just doesn't mix well.
Westbrook, Wade, and George has a lot of similarities to Rondo, Wade, and Butler. Westbrook is better of course, but the way they play and the problems of fit would be very similar to this years Thunder and last years Bulls. Yes, Melo is a better SF/PF option than the Bulls had, but with how many players need the ball, he'd be relegated to a smaller role that could only be slightly more prominent than the one Mirotic played last year. Obviously they won't be as bad as that Bulls team, but that Bulls team was hyped up as being a contender for HCA last year, and I kept saying they wouldn't come close because of the problems of their top players fitting together.
So this type of situation is what I'm talking about when I say OKC could get overhyped because mosts are just focusing on the names they have and not how they actually fit together.