I've been an Ayton detractor, but seeing the Suns' collapse against Dallas puts me in the keep-Ayton camp as well.
The Suns' window with Chris Paul has closed. The question now is whether it's possible to retool for another run before Booker's career is over, or before Booker gets fed up and asks to leave. So the Suns need to make personnel decisions with a view to building a contender three or four years from now.
Given that, Ayton is the best option at center. He's limited and probably won't get significantly better, but he's still a credible presence on both ends of the floor, and it's rare that the Suns have been able to say that about their center.
The Suns will be restricted financially as long as Paul is on the books, but, looking beyond that, the contracts given to Booker and Bridges aren't that bad, and even a maximum extension for Ayton will look relatively affordable by the time Paul hangs it up or is bought out. So it's a long-term investment for a second-tier center -- an overpayment, yes, but not a tragic one, given the tightness of the market.
To me the more difficult question is what to do with Cameron Johnson. Like any sixth or seventh man on a good team, he has his strengths, and replacing his skill set won't be easy. But the reality is that he'll turn 27 in the middle of next season and has pretty well established that he'll never be a consistent impact player. In the four losses against Dallas, when the Suns needed him to step up, he averaged 8.5 points, 3.8 rebounds, and 1.8 assists, in a fairly generous 22 minutes per game. Does anyone really think that Johnson is going to have a crucial role on a championship team a few years from now, as he rounds into his 30s?