I think at this point, it might be unlikely that we're getting more than just cross gen evos. Normally Pokedex changes are covered in the first batch of news for the games, and they've said nothing about the Pokedex aside from that the first 12 or so Pokemon in the Hoenn Dex are the same (which doesn't really say much, because that's just the starters and Zigzagoon and Poochyena lines). So if there were going to be any major Hoenn Dex enhancements, we'd probably know by now.