This is wishful thinking, of course...
...but I think a new Fighters Megamix with franchise representatives from Namco, Sega, and Capcom would be quite cool. Namco brings Tekken and Soulcalibur, Sega brings Virtua Fighter and Fighting Vipers, and Capcom brings all their fighting games (Street Fighter, Darkstalkers, Rival Schools, etc.). It would be a fun romp.