Definitely won't opt in to an $18m contract
I always thought the most likely move for Kyrie was a 1+1 contract in Boston and push to get AD, align his free agency with him. Give it a year, if it didn't work out next year they both leave to go wherever they want to go. But the negative reaction from the fan base holding him solely responsible for our failure to meet expectations (particularly the difference between his year 1 and year 2) made me reconsider. Because who wants to play for people who hate you? LarBrd is obviously taking it to an extreme but Kyrie does seem to have that type of personality where being loved and being happy might be more important to him than being on the best team. That's when I thought Brooklyn or NY might become more realistic destinations for him, a chance to shape a team in his image. I think he thought he had that here, but he got injured and the young guys he was trying to shape went to the ECF without him and they all developed big heads as a result.
Assuming he would leave Boston, I never thought it was likely that Kyrie would team up with KD in Brooklyn or NY though. If KD went to NY i thought Kyrie would go to Brooklyn. Because I can't see Kyrie returning to a scenario where he was second fiddle again. He wanted his own team. So 2 years after having his own team he gets dumped out of the playoffs and crawls to another team with a better player, tail between his legs, basically admitting he couldn't do it? I can't see it happening. Not for LeBum, not for KD. Those two guys would suck out all the oxygen in the room and there'd be none left for him.
Whichever player he plays with would have to be willing to play second fiddle. I think he would be willing to play with AD, in Boston, because AD kind of has a beta personality and Kyrie would still be the face of the team even if AD was the best player. It could still be "Kyrie's team". I'm sure Danny will ship out whichever malcontents Kyrie wants shipped out.