Also not any different from putting Snake in Brawl when there was only a single post-NES Metal Gear on Nintendo systems.
Hey, don't forget about Ghost Babel on Gameboy Color.
I remembered it after I posted lol, but... yeah.
Snake was in four games on Nintendo platforms (five counting the Konami Smash Bros. knock-off that came out before Brawl) and The Twin Snakes was a Nintendo joint with Konami and LOLOL Silicon Knights.
Now look at Street Fighter. There's 2010 on NES which shouldn't even be counted, then the SNES games and GB ports...and the only recent thing was SSF4 3D Edition in 2011. But whatever. I'm down for Ryu.
Metal Gear
Metal Gear 2
Metal Gear: Ghost Babel
Metal Gear Solid: The Twin Snakes
Street Fighter 2010
Street Fighter II: The World Warrior
Super Street Fighter II
Street Fighter II′: Champion Edition
Street Fighter II′ Turbo: Hyper Fighting
Tatsunoko vs. Capcom: Cross-Generation of Heroes
Tatsunoko vs. Capcom: Ultimate All-Stars
Super Street Fighter IV: 3D Edition