How to have made ORAS not shit:

1. No free Lati@s. You get the Eon Flute after gym 5 for Soaring, then you can capture Lati in postgame. Soaring is tied to the item anyway, you don't even need the mon.
2. Emerald gym teams + gym leader rematches with megas.
3. Bring back held exp share. Party exp share only available in postgame.
4. Unnerfed Granite Cave and Sky Pillar
5. Unnerfed contest mechanics and berry blending
6. Unnerfed Safari Zone
7. No teleporting
8. No free Rayquaza against Zinnia
9. At the very least have Battle Factory. It's the facility everyone wanted and it's the easiest to implement. Just use Maison's Pokemon.
10. Game Corner replaced with Mauville Arcade, literally just port in Pokemon Pinball R&S. It'd take up very little space on the cart (plus it's a criminally underplayed game). It's like in Ninja Gaiden on Xbox where you could play the classic SNES games in the arcade.

None of these require a ton of additional work, it's just changes in design rather than extra content, and the extra content is just porting old content. The safari zone is probably the hardest part, but the new one is inexcusable.

I consider this the bare minimum for the game to have been decent.