A challenger emerges
Sonic in Smash Bros!
I am really surprised. I was so sure that Mario and Sonic at the Olympic Games, with its perfect 50/50 split of the title, cast, and even official artwork, was a sign that the companies' respective legal departments would never accept anything less than perfect equal billing for any crossover game. (Kind of like how Mickey and Bugs Bunny were required to have identical amounts of screentime and dialogue in Who Framed Roger Rabbit.)
But clearly I was wrong! Sonic is going to be one of the many playable Smash Bros. fighters after all. And after seeing how well Nintendo has handled Snake's inclusion, heck... they're almost certain to treat Sonic with more care than Sonic Team has been lately.