I like Ryu, but unless his inclusion is meant to advertise a Wii U/3DS-exclusive
Street Fighter game or a "Nintendo vs. Capcom" crossover, he doesn't really have any apparent reason to be in
Smash aside from his iconic status. On the other hand, every other third party character featured so far had that merit going for them and then some.
- Sonic and Mega Man were both highly requested for Brawl and Smash 4, respectively. The former character managed to return in Smash 4 presumably for the sake of promoting Sonic Lost World and Sonic Boom, both of which were exclusive to Wii U and 3DS thanks to that contract with Nintendo and Sega.
- Snake was in Brawl due to Metal Gear series creator and Sakurai's best friend Kojima's personal request.
- Pac-Man was in Smash 4 due to Namco's involvement as a co-developer, and...well, he is their mascot.
Ryu seemingly came out of nowhere.