What I don't understand is the "intangibles" category. This is completely subjective, and yet the Lakers get +150, and the Celtics get +50, despite being the most successful team in NBA history. The Celtics tradition and history is every bit as successful as the Lakers.
For the rest of it, who cares about playoff wins and losses, in terms of evaluating a franchise? All that matters is the last game of the playoff season, and there, the Celtics have the most wins.