Acquiring LeBron and Bosh was a total success for the Heat franchise. They went from barely having attendance to the hottest ticket in the league. And four straight Finals appearances isn't anything to snark at. So what they only won half of them.
Now, for LeBron? A guy that is put in the same annals of Jordan and such, winning more championship series than he lost was big for him. And he just didn't do that. Being 2 out of 5 in finals is going to hurt his rep some. It's unfair, but such is life.