My ideal list:
August: Wolf, Ice Climbers and Snake: BOOM! Ice Climbers are still a pair but reworked, Olimar-style, to function on WiiU and 3DS. Snake is the big surprise, bundled with Shadow Moses Island. No codecs, and VA is recycled from Brawl, but he's a great surprise, and timely too, with MGSV coming out in September. (Not unlike Snake in Brawl around the time of MGS4). And Wolf is Wolf. The three most wanted veterans, no doubt.
October: Pichu, Squirtle and Ivysaur: The Pokemon pack. Saffron City 64 is also presented, updated with models popping out of the building. Another stage is Pokemon Stadium 1, which first appeared in Melee and would also work well on 3DS (where there are no stadium stages). All three Pokemon now have their own Final Smashes. Squirtle and Ivysaur each have a new Down Special move.
December: Dixie Kong and K. Rool: For a Christmastime Direct, Sakurai unveils the winners of the Fighter Ballot, planned for release in Spring 2016. The two DKC characters were among the top vote-getters and Sakurai agreed they'd make interesting characters.