>>56071651oh boy, there's a lot to unpack here.
so first of all, I know for a fact that all of the current mons and most new mechanics including megas have been ported into emerald by now. I would be very surprised if one of the billion emerald enhancement hacks didn't update the battle frontier with this stuff.
it's probably not going to meet your specific preferences. nor would I expect an "ORAS-ified" romhack, because frankly most of the changes to ORAS weren't favorable changes, so why would you want to back port them?
the question posed by the OP was about why nobody has hacked the battle frontier into ORAS. this is because it's easier to replicate having ORAS MONS AND ABILITIES in the emerald battle frontier than it is to build an entirely new battle frontier in a different game. nobody said anything about recreating the entire ORAS experience in emerald or vice versa. it's about the battle frontier only. and if you're playhing the battle frontier, it's for the mechanics, not because you really love staring at ORAS graphics or whatever. so you're not losing anything by replicating the mechanics in Emerald. you would still have all the new pokemon, megas, the phys/special split etc. and it would play functionally the same. I don't actually know if such a hack exists, again I would be surprised if it didn't, but whether it does or doesn't it would still be easier to achieve because all those pokemon and mechanics are there, it's just a matter of updating the battle frontier. whereas building a battle frontier in ORAS would be a much larger undertaking.
