Previous games in the series had subtitles -such as Super Street Fighter II having The New Challengers as a subtitle. Some promotional material for this game had The Ultimate Championship as a subtitle, but this was dropped in the end.
However, the sprites for this are still in the ROM.
More unused text. There was an 8 player version of Super Street Fighter II called The Tournament Battle. It was possible that Capcom planned an 8 player version of this game and given it this The League Battle subtitle, but then changed their minds.
If you finish your opponent with a super combo, you'll get a special flashy background. However, it was originally intended that you could get this background just by finishing your opponent with special moves, as these screens prove.
In 1994 there was a fighting game tournament in America which featured a playable prototype version of the game, some players remember there being differences. Zangief's crouching roundhouse would cause chip damage when blocked -this was most likely a glitch and was fixed for the final game. Ryu's forward strong and fierce punches were apparently slower than in the final game. You can see people playing the prototype version here.