In my opinion a split isn't necessary. The differences are mostly superficial. The versions of the game play out the same way. The differences I'm aware of are:

-fewer text boxes -JPN MG flies into the battle -USA MG is revealed through fog -USA MG skin removal animation -MG super fire breath cutscene -MG death animation

It's typical for speed games to be faster in Japanese due to various minor reasons. If you look at popular speed games such as Super Mario 64, Ocarina of Time, or Super Mario World you see most boards dominated by Japanese platforms. Speedrunners are naturally going to gravitate towards the faster version of the game.

Besides, our board is so small right now I'd hate to see our already small community divided. I'd like to find ways to share this game with the world, I think it has a bad reputation it doesn't deserve.