Here's the problem with that.
Wade and LeBron play decent iso defense. The Spurs rarely play iso ball. Therefore you negate overrated isolation defense. When you have 5 scorer, 2 guys aren't going to be able to deal with them.
LeBron and Wade also can't guard Duncan in the post. You're forgetting Duncan's been trashing teams this year, especially in the playoffs. He destroyed Jefferson in the first round and beat the brakes off of Blake Griffin in the 2nd. Now in the WCF, neither Thunder big can score on Timmy, and Duncan's breaking the rim off dunking in Ibaka's mouth.
Dirk's worst series was the Finals btw, he didn't dominate them. He dominated every series before the Finals, and was pretty average vs Miami.
Right now the Thunder are a better team than the Heat. . .and SA is up 2-0. Heat aren't giving them any extra trouble. Spurs in 4 if Bosh comes back looking limp. Spurs in 5 if he comes back looking okay. 6 if he comes back 100%. Won't go 7.