It's true that, in the final assessment, regular season doesn't matter. Playoffs are the only measuring stick in the NBA. But that doesn't mean that an assessment made now should be diametrically opposed to assessments made during the regular season, or even during the playoffs previously. The fact is this: up until Tuesday night, the majority of NBA players, coaches, and writers asserted that the Cleveland Cavaliers were the best team in the NBA. They were considered a much better team, for example, than the Cavalier team that went to the Finals against the Spurs a few years back. That team, even when it was winning, was considered a one-man squad. This current team was not, and it's only now that they've lost twice in a row in the playoffs that suddenly they also are a one man team. It's revisionism, and I reject it.
The Cleveland Cavaliers are a better team than the Boston Celtics. They are a better team than the Orlando Magic. They are quite possibly a better team than the Lakers. They lost because LeBron played poorly in the 4th quarter of game 4, in all of game 5, and in game 6, and because Mo Williams did not play well in games 4 and 5. They also lost because their coach made awful decisions regarding substitutions. I think that LeBron played poorly due to injury, though we may never know the truth.
If LeBron returns to Cleveland, the Cavaliers will still be one of the 2-3 best teams in basketball, and with the addition of a quality shooter (Joe Johnson? Ray Allen, even?) that might be enough to get him over the top. Because it takes a while, usually, for team chemistry to gel, I am not convinced that if he chooses to leave he will be any closer to a championship anytime soon than he is right now. Therefore, it seems to me that the possibility of him sticking around is still pretty good at this point.