I think it takes time for a team to gell. Besides, there is way too much talent in the league to let any one fantasy team win 70 games.
Besides, Miami nightlife has enough distractions to shave off at least 5 wins a year. Hence you predict this team to go 76 and 1 - NOT.
Maybe when all the old stars retire by 2013, and the while the rest of the teams are rebuilding, the Heat could run roughshod over the league and put together a fantastic season to be compared to the 1996 Bulls, the 1987 Lakers, and of course our 1986 Celtics.