They gotta keep Wade, he's Mr Miami. But I think they would do well to trade Bosh and Chalmers away. Who's going to want them, though? - Mike Miller is not a guy who should be on the court for 20 or more minutes, he should come off the bench every once in a while to drop some threes in. He's always scrambling on defense. So despite winning the championship, changes need to be made, and they can get substantially better.
Chalmers is a starting guard making just $4M (team option). I think some team would want him, but I don't think we've seen enough from Norris Cole for the Heat to send Chalmers packing. Although Miller has been frequently mentioned as an amnesty candidate, he's making about the league average. His problem has been injuries have kept him off the court but as he showed in the playoffs, he's a valuable shooter when he's getting playing time. He could be expendable because the Heat have Ray Allen and Shane Battier.
I suspect Micky Arison will elect to keep the Big-3 together for one more rodeo, and pay whatever the inflated luxury tax will be. I'm of the opinion that on the Heat, Chris Bosh is massively overpaid but I don't see any team willing to absorb the $60M remaining on his contract. Game 6 "heroics" aside, certainly not after the donut he laid last night. If Bosh opts out in 2014, I imagine the Heat would politely show him the door.
All bets are off next summer though as LeBron is likely to opt out, and it'll be interesting how he, Wade and Bosh decide to handle potential free agency in a much harsher luxury tax environment. I imagine LeBron wants to stay in Miami, but who know what happens if Wade and Bosh decline their opt-outs and James gets bowled over by another team.
Miami has an advantage that James can recruit a solid role player with peanuts for the lure of a ring, but otherwise I wouldn't say they can get substantially better. The new CBA hamstrings all the big spending teams and unless you're Mikhail Prokhorov or the Lakers desperately wanting DH back, the $100M payroll will become a rarity for a half decade.