The Heat's combination of talent at the top of the roster is almost unprecedented.
Hardly. The 00s Lakers had 2 top 5 players; the 90s Bulls had two top 5 players; the 80s Lakers had two top 5 players (plus a number one pick and HOFer tacked on to that) and the 80s Celtics had three top "something" players (top ten? fifteen? I'm not sure how Parish and McHale ranked at that point).
The Heat meanwhile have the best player, another player toward the bottom of the top 8, and another player toward the bottom of the top 20. They have no center and no point guard. Ray Allen has been about as good and no better than any other starter-ish 2 guard would have been and Rashard Lewis doesn't play. Shane Battier and Joel are offensive nonfactors (in fact liabilities except for Battier's wide open 3s, which he manages to make fewer than 40% of) and they're one of the worst rebounding and interior defensive teams in the league.
Their two best players are the same player and neither of them are very effective outside of fifteen feet. Their third best player is 7 feet tall and is not very effective *inside* of fifteen feet.
I used to think the Heat were too stacked, that the Lakers were, that the 08 Celtics were... but they're really not. That just play great team basketball and have great roleplayers and a couple great stars. How can we ask that our top teams be made any differently? We've proven time and time again you can't just stack a ton of great players and win a title (remember Hakeem + Chuck + Pip? How about Howard + Bryant + Gasol + Nash?). You have to have a team, and your top players are only one part of that dynamic. (And, as the 04 Pistons proved, a totally unnecessary one.)