WTF is wrong with you all?
Looking back on the general “Third Version” formula (drawing on past experiences from Emerald and Platinum, specifically), a game’s third version would allow you to catch both of the version mascots in the previous two games while focusing on the third member of the trio.
For the Black/White games, -this is impossible-. You would have to either rewrite the game’s storyline or give N some shitty excuse to release the legendary he caught, like believing himself to be unworthy or some other lame-ass bullshit.
Do you really want N to puss out that hard? He’s the only rival character so far who has managed to legitimately catch a legendary pokemon. Do you really want that to only be temporary, or worse - retconned?? I much rather prefer him flying off into the sunset with dignity and grace, as I’m sure many of you do.
Next, I’d like to remind you that Gold and Silver were direct sequels as well, and they kicked ass.
So, for those of you who are thinking (and perhaps even saying out loud, god damn you all) “tl;dr”, let me sum it up for you:
Quit being stupid and writing shit off. The sequels are going to be awesome. Deal with it.