When Collins was at his peak in ATL, he was a ~23 USG guy who was super efficient and one of the best, if not the best PnR roll man in the league.
This season, he's a MUCH higher usage guy (albeit less efficient of course). 28% USG and 58 TS% which is not bad at all. Only 9% of his possessions are as PnR roll man as opposed to 28% at his peak. He's doing things in different ways an excelling. The versatility with his playmaking and high post play is allowing him to play with other bigs which is a huge bonus. He was a decent PF defender in ATL and has also upped his intensity to be more effective on that end.
I don't know if there's a trade partner for John Collins, but I would not mind making him a long term piece.