I really wonder how they're going to make the Pokemon Bank support work. The whole reason Gen 1 and 2 Pokemon were incompatible with the later games in the first place is because of the huge changes to the IV and EV system made with Gen 3. If I remember correctly, back in the old days Pokemon only had four IVs (or DVs, as we called'em: Attack, Defence, Speed and Special, which ranged from 0-16 rather than 0-31), and their EVs (which we called EPs) didn't top out at 510. You used to be able to max every stat.
Long story short, Pokemon from Gen 1 and 2 were significantly beefier than Pokes from Gen 3 onwards. You didn't have Natures to get the extra 10%, but in return you had sweepers with maxed speed, attack and defences, and battles were grudge matches where you needed Toxic on everyone just to try and whittle away at massive defensive walls. It'll be easy enough to split the Special stat into SpA and SpD (they already did it automatically in G/S/C), but I wonder how they'll deal with the EVs. The easiest thing would be to reset everything to 0 upon transfer, but then you'd have people wondering why their beastly Mewtwos turned into busters all of a sudden.