I've actually talked about this in one of the threads.
As a cynical sort of person, I'd go out and say that Game Freak excluded all of this stuff that should have been included so Black and White 2 would look just that much better when it released. So taking out features that should have been in the first and add it as a hook to get you to buy the next game.
This has been a trend going on since Emerald. Or maybe Crystal, it's been so long since Crystal I can't remember what differences have been made between GS and Crystal. I know a lot of my friends that skipped getting Black and White 1 for the assumption that Grey was getting released so they wouldn't waste money. We all know this trend.