I skipped B/W for that very reason, then B/W 2 came out, screw it, I thought, there is no definitive version (Like platinum), and I think Nintendo might like the extra money B/W2 bought in, so I'll go with X, thanks.
I can't really wait and I thought both BW and B2W2 were great on their own. B2W2 did not replace BW with a few small changes, it was a completely new game in mostly the same region. I would be happy if they continue the sequels thing, instead of just a pokemon Z with the same story with a few new things.
So yeah, I'd get both X and X2, but I wouldn't really want a Z.