Just announced, Nintendo added 4 games to the Sega Genesis part of the expansion pack! The games you keep saying the Expansion Pack isn't worth it for will be Sega classic Flicky, the never ending and cosplaying platformer Kid Chameleon, the colorful Pulseman, who is made by a certain Pokemon creator, and the fantastic Street Fighter II: Special Championship Edition. That last title obviously plays online!
You can check the video below. Looks like the games are continuing to come. June is two months away, so if we get an E3-esq presentation, Gamecube is next. What if they add Wii titles?! The possibilities are endless.