Eh, I don't really care about what they decide to put in the national dex.
First it was supposed to be cool that the region didn't feature any old pokemon, now it's supposed to be cool that it does. :P
A National Dex without old pokemon is cool for the start of a generation. That way we can easily adapt to the new designs and it'll be difficult to ignore them.
A National Dex with old pokemon is cool for the end of the generation. A generation diversity would make B2W2 feel different from BW, and people with nostalgia goggles won't complain as much. :P
Although, like I mentioned in a previous post, most of the older ones they've added in so far are Pokemon you can get normally get in Black/White Post game and from the White Forest.
Kinda like they did for Platinum version.