Being a star that will soon begin to fade, with ~100m salary, Messi is a controversial asset even from the business perspective now. He can financially destroy the club he'll join. And as a person and a team member, he's a toxic wayward kid whose response to facing a problem is to quit (he did it with both the club and NT that worshiped him). I know it will never happen for a lot of reasons, including money, but if Juventus were to sign Messi, it would be the worst thing they could do in the current situation.
It would be interesting to see him at Inter though. They have filthy rich owners, Messi is a huge brand in Asia as well, and they can seduce his entourage with all the options Italy can offer when it comes to taxes, etc. But he'll probably just join Manchester City. Since they already successfully avoided severe consequences after ignoring FFP, they can afford not to care about it whatsoever. Also, winning with Inter would be quite a challenge, and there's a risk to be humiliated by CR7 who already proved to be a big champion in Italy as well. That's too much of a risk for such a fragile personality.
Or Messi will just stays put. As he usually does after such hysterics.