This game must have some kind of cross-generation backwards compatibility with Diamond, Pearl, Platinum, HeartGold & SoulSilver cause with it being released on the Nintendo DS it would be obvious that you can trade Pokemon from the Black and White versions with Diamond, Pearl, Platinum, HeartGold & SoulSilver right?
I just don't see why Nintendo wouldn't do that, the game is going to have a National Pokedex with the Power Items and stuff as usual with extra features I'm sure. I'd just hate for Nintendo to force everyone into starting over from scratch on Black and White not being able to still use their Pokemon from the previous versions on the DS.
It makes for Wi-Fi battles being geared just on the 5th Generation with no way to get Pokemon from other games especially Items from other games as well like the Power Items, Pokerus, that sort of thing. Serebii.net did mention that there will be some kind of cross-generation backwards compatibility with Black and White but they didn't say that you could trade Generation 1, 2, 3, and 4 Pokemon with 5th Generation Pokemon in Black and White in some kind of detail via Wi-Fi trade.
As for Pokemon not being able to follow you anymore like in HeartGold & SoulSilver it's sad that you can't do that in Black and White. It was a nice feature to say the least but all I'm really concerned about is whether If I'll be able to transfer my Pokemon from Platinum and SoulSilver onto either Black or White whichever version I decide to get.