Next year seems like it could be a tough one for the 3DS. No new Pokemon X/Y to lean on ... perhaps Capcom will push out a Monster Hunter 4G or something but that probably won't push as many new systems as they have most of the MH fanbase now on board.
Dragon Quest XI is probably still a ways off. Mario is spent I think, they need to give him a break (no, Nintendo, just say no to rushing out a New Super Mario Bros. 3 next holiday).
Smash Bros. 3DS yeah, but I wonder if that's a more console centric franchise. If I could only buy one of the two versions it would be the Wii U one, that seems to be something that would work a whole lot better on 40+ inch HDTV with friends in the same room.
Of the big franchises left that haven't appeared on the 3DS yet -- Kirby (coming), Mario Golf (coming), Metroid (who knows), new Star Fox (who knows), F-Zero (I wish), Advance Wars (yes please), Punch-Out! (sure why not), Wave Race (doubtful) ... these are definitely not the bigger Nintendo franchises.
Square-Enix isn't pulling their weight on the 3DS like they were on the DS IMO. Where's the Final Fantasy V, VI, or (gulp) VII remakes? Why is DQVIII on cell phones and not 3DS?