ORAS was good. Sure, no battle frontier or game corner, but what about all the other cool stuff it brought to the table? Soaring and mirage spots were fun to explore. You can have both bikes in your inventory at once. The PokeNav Plus alone adds a lot of depth. It’s probably the easiest game to shiny hunt in.
On top of all the new mechanics and features after Gen 3, ORAS has a spectacular foundation of the Hoenn games themselves, which were already designed really well the first time around.