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Should Black 2 and White 2 have been some kind of DLC or expansion to Black and White instead of full games? Did Game Freak rip us off? Not trying to troll, but seriously think about it for a second. The purpose of BW2 was supposedly to tie up some loose ends about what happened to N and the land of Unova in the years following Black and White. At its core, Unova is essentially the same with the exception of a couple of new areas added and the world tournament. The new areas held some of the Older Pokemon to catch... but really most people had access to previous generations or the Dream World at least, so they could still get some of the older gen Pokemon.
All of this could have been provided through the 3DS shop somehow as DLC. I understand that BW were regular DS games and hence had no save data on the 3DS Memory Card... but I'm sure Game Freak could have pulled something out of their ass to alter the Game Card of you Black or White game to have DLC. Or maybe some weird game pack add-on where the DLC is played through your original Black or White version.