how about to the mavs?
Miami should've got that one on talent, yeah but that was their 1st year playing together and they really hadn't assembled much in the way of roleplayers yet (Battier, Allen, Birdman)
Dallas was a good team though, swept LAL and beat OKC in 5. Were they an all time team? No, but I don't think losing to them is awful or anything. I'd say it was LeBron's worst loss though. Especially his play in the 4th quarter in that series was pretty subpar.
He did follow it up with 2 titles beating OKC and SA in the finals. These teams weren't exactly slouches.