MeeMee has been confirmed as a playable character.
I have to admit I'm disappointed with some of these character choices. I want to see as many Sega franchises represented in playable form as possible, yet they're doubling up on characters from the same franchises. It's been said that there are going to be 29 characters in total, and we currently know 23 of them. We don't have many left.
So far, here are the Sega franchises that have playable reps:
Sonic
Jet Set Radio
NiGHTS
Space Channel 5
Super Monkey Ball
Shinobi
Skies of Arcadia
Samba De Amigo
Crazy Taxi
Golden Axe
Total: 10
Here are the Sega franchises represented in Sonic & Sega All-Stars Racing:
Sonic
Super Monkey Ball
Samba De Amigo
Billy Hatcher
Jet Set Radio
Space Channel 5
Crazy Taxi
House of the Dead
Shenmue
Virtua Fighter
Bonanza Bros.
Chu Chu Rocket
Fantasy Zone
Alex Kidd
Total: 14
It's possible we could end up with a greater amount of franchises represented in Transformed by the time all the remaining characters are revealed; we could in theory see 16 different Sega franchises represented in a best-case scenario. But that's only 2 more than it's predecessor, and considering there are 6 more characters overall, I still think doubling up on Jet Set Radio, Super Monkey Ball, and NiGHTS characters is a waste. I half expect to see Pudding too, as along with MeeMee, Gum, and Reala, she was a second rep for her respective franchise in Sega Superstars Tennis.