By 'mistake' I meant untrue to the show, i'm sure you knew that.
Anyway, heres the official list of special playable characters, some of which don't have pics [spoilers]
Bardock
Broly (Normal, LSSJ)
Cell (Imperfect-Semi-Perfect (no super perfect))
Cell Jr.
Coola (Changeling form 4 and 5)
Metal Coola
Freeza (First, Third and Fourth form (no 100%? no second form?)
Saibaiman (yay...)
SSJ Gogeta
SSJ4 Goku
SSJ4 Vegeta
SSJ4 Gogeta
Uub (and Uubuu)
Syn Shenron (Syn+Omega)
Which means the rumours of Janemba, Tapion, Garlic Jr and the Shadow Dragons were just that, rumours, also Super 17 was said to be in it but he's not on the list. Maybe they're holding back a few things. It'll be very interesting to see how they attempt to do the GT saga's without Baby.
EDIT: New Characters in the intro: Uub, MetaCooler, Broly,
Gogeta, SSJ4 Goku, Syn Shenron