I don't care if even Mahorn disagrees, the Bulls/Heat game on national TV was truly a flop of a game to watch when you have Portland/Boston on at the same time! And don't give me this "buy the League Pass" crap. Just more money in Stern's pocket. If the NFL can do it, why not the NBA?
It's easier for the NFL because the "flex" part of it just comes in which time of the day the game happens on Sunday, not which day it is. This is tougher to handle for the NBA because games are on almost every night of the week. Now it'd be nice if the NBA could switch the national TV game to a different game on the same night; I'd be totally in favor of that, like your example of switching from Miami-Chicago to Boston-Portland. Why they can't at least do that is a good question.