Originally Posted by
Polarthief
There's a huge difference between "all the Gen 2 pokemon would be incredibly weak and bad due to how IVs are changing" and "a large amount from past generations aren't allowed because it'll take too long". Plus we have the remakes of Gen 1 (both in Gen 3 and 7), Gen 2 (in Gen 4), and the Virtual Console releases of both on the 3DS, BOTH of which allow you to transfer 'mons to Pokemon Bank (and it changes their IVs to the new system, I assume randomly).
I'd prefer the game delayed a full year to 2020 or even later (or patches thrown in as time goes on) to allow EVERY Pokemon in than this solution. "Gotta Catch em All", more like "Gotta catch only the ones we decided to improve".