Can't believe I forgot about Tangle and Whisper in my earlier post; yes please. Would love to see them be playable in a main series game.
Knuckles was never a villain; Eggman tricked him into believing Sonic wanted to steal his Master Emerald.
She's at least got that appearance in official art to let us know she CAN appear in Classic Sonic media.
Just a shame that she can ONLY appear in Classic Sonic media now; same for the Hooligans. They really need to let go of those mandates; Honey's appearance in the short lived Archie Sonic reboot was great.