If we do get DLC, Big needs to be the friend helper character.
I've completed the game now. S-ranked all the bosses and Rivals on normal and Hard mode and now working on the red star rings.
EDIT: Whoios, seems I've posted about the Big stuff before.. Oh well.
I'd kill for another era to be added via DLC, with Big, Jet and Omega being the three extra characters. It doesn't seem likely though considering what we got with Unleashed and '06.
I see there being 5 options they could follow.
1. We get a new era of about 3 or so new levels, maybe another rival or a boss (I'd love to have a classic Knuckles fight). I feel like the games that would be represented here would be Sonic 3, Shadow, and Sonic and the Secret Rings, unless they want to go into left field and pick a portable level, which in that case scratch the last two and put in something from the Advance series and something from the Rush series. Regardless they'd be silly not to include Sonic 3 if they were making new levels.
2. We get new levels using the resources from the boss battles and such, so we would see stuff like Stardust Speedway, Final Chase, Death Egg, Casino Night, and Eggmanland
3. We get an actual new act for the levels that already exist
4. We get hard modes and challenges and stuff.
5. MOAR PINBALL
And then of course there is the chance they won't do anything. While it seems unlikely because of Unleashed and 06, Unleashed did at least make new acts so I'd say we have a chance for that at the very least. Personally I'd like to see them expand the selectable music menu as well, but mainly to apply to every song already in the game. So if I want to play Modern Planet Wisp or original planet wisp in classic Planet Wisp of if I want to play that Sonic 3D Blast theme in sky sanctuary I'll go ahead and fucking do it.