These are the career best seasons (as if they had them all in one season)
Wade - 30.2 p, 7.5 a, 6.4 r, 2.2 s, 1.3 b, 58.8 TS%, 30.4 PER, 14.7 WS, 10.7 BPM, 9.7 VORP
Pierce - 26.8 p, 5.1 a, 7.3 r, 2.1 s, 1.0 b, 62.0%, 23.6 PER, 12.9 WS, 4.9 BPM, 5.7 VORP
Here are some awards and high level award finishes
Wade - 13 all star, 8 All NBA (2 1st, 3 2nd, 3 3rd), 3 2nd Team All Defense, 2 top 5 MVP, 5 other top 10 MVP
Pierce - 10 all star, 4 All NBA (1 2nd, 3 3rd), 1 top 10 MVP
I mean looking at the breadth of the career bests and all of the yearly awards it is pretty darn hard to say that Pierce had a better career. I mean objectively it is basically impossible, and frankly I'm not sure you can honestly use subjective standards either. Wade was just flat out better than Pierce.