Just because he has a good relationship with his former teammates and enjoys being around him does not mean he regrets being traded. Would Micah have been happy to get paid and stay in Dallas? Sure, he's made that clear. He and his agent even made a last-ditch effort to make that happen, when it was too late in Jerry's mind. Ultimately, like most players, though, he just wanted to be paid what his agent says he's worth.
These players look at the game much more from a business standpoint that fans do. Does George Pickens want to stay in Dallas? Sure, if he gets paid enough to do it. In that, he's no different than Parsons or any of the rest of them.