They don't even need to create any new region or any new pokemon! Just improve a pair of old games for what? Right, alot of money.
And even if all the pokes are available, it would make some of them much easier to get with a Johto game (instead of like some idiotic crap like getting a GC game, GCN-GBA cable, and transfer to DP...........)
Consider that, people will buy those like hell, everyone who missed them and those who found these were the best generation. If Gamefreak don't use this opportunity, they're really stupid.
It's not that the fact that money (yes money people), will allow Nintendo to sell the game like porn, it's the fact that 'when' they decide to create it is the problem.
Heck, the only reason on why I'd like to see it get re-made was not only the fact that you can go to Kanto (and fight real weak Gym Leaders excluding Blue), but the fact that a DAY/NIGHT system was introduced and back then, after a good rough 6 to 7 years, the battery would run out :(.
...Now think of what would happen when Nintendo SHOULD release G/S/C for the DS (or the DSi that people have gotten interested into), you'd never need to fear about the ability of your internal battery running dry (as the day/night system wouls run off the DS Clock).
Listen to me ramble like a silly old food ;). Yes, as I said earlier, I'd like to see a remake of G/S/C happen...... if it's to make pointless money for people to play it, why not?! I ain't bothered wether they change the difficulty or not (chances are they won't so you'll find the remake to be remarkably easy), but for once, JUST ONCE, I'd like to see all those 'beta' maps that weren't in the original G/S/C to appear in the remake (should it happen).
.....And that ability where capturing Celebi is possible (instead of using a damn AR).
Edit: also forgot to add the fact is WHEN Nintendo decides to 'bother' to remake G/S for the DS. Some might 'think' it'll happen..... and I must say, kudos to them as what they are wishing for is near to nigh impossible :(.
.....Let's just pray a miracle happens and Game Freak decides to pleasure us with G/S announcement ^_^