I'm too lazy to look it up, but is Thomas Robinson an elite rebounder? I always viewed him as lower than average for a PF. And decent defensively? Tristan and Thomas are in totally different classes defensively from what I remember. Tristan is pretty good all around and Thomas doesn't try hard. At least that is my knee jerk reaction of the two.
Tristan Thompson has a career average of 10.6 rebounds per 36 minutes, while Robinson's is 12.2 per 36, so Robinson is the better rebounder statistically. Basically the two average identical offensive rebound numbers (4.3 vs 4.2) but Robinson is a better defensive rebounder (8.0 vs 6.3)
In terms of defense, Thompson ranks 60/73 among active centers with a Defensive RPM of -0.42, while Robinson ranks 59/80 among active power forwards with a Defensive RPM of -0.18, so statistically Robinson is also a slightly better defensive player both overall, and relative to others at his position.
Thompson has averaged 12.7 points per 36 for his career on 49% shooting, while Robinson has averaged 12.9 points per 36 on 46% shooting, so Thompson looks to be a slightly better offensive player.
Both players have averaged 0.9 blocks per 36 for their career, but Robinson has averaged more steals (1.3) than Thompson (0.7).
Similar turnover numbers per 36, with Robinson averaging 2.7 and Thompson averaging 2.3 (per 36).
Both players have shot the same percentage for their careers from beyond 16 feet and from within 3 feet, Thompson has shot significantly better from 3-16 feet.
Both players do a good job of getting to the line (43% FTR for Thompson, 36% for Robinson) and both shoot a similar percentage there (64% for Thompson, 60% for Robinson).
All things considered this comparison by the O.P. actually isn't that out of this world. VERY similar statistical profile for both players pretty much across the board with the exception one or two areas (midrange jumper in Thompson's favor, defensive rebounding and steals in Robinson's favor)