It'd be cool if instead of being able to train higher than the elite four you have to learn tactic, so they're 90-100. Maybe you would have to collect more badges, or it could be higher than the elite four and you have to beat the Kanto and Hoenn elite fours to get into it....That would be cool, as well as traveling to Kanto, Johto, and Hoenn. Even the Orange Islands since they havent been in a gb game yet.
I'm hoping for a longer and tougher game so around 65-75. Some might say it's too hard but the elite 4 should be elite, not just some random trainers who's teams you can sometimes wipe with a single pokemon.
Also a reason to ditch the elite 4 mono types