I just realized something; we don't have as many "surprising" characters for this game as we think.
Let's see what surprise characters we do have:
64:
Captain Falcon
Melee:
Ice Climbers
Zelda (to an extent)
Mr. Game & Watch
Dr. Mario
Young Link
Roy
Pichu
Brawl:
Snake
Pokémon Trainer
R.O.B.
SSB 3DS & Wii U:
Wii Fit Trainer
Gekkouga
Rosalina
Chorus Men
64 had one, Melee had seven (and would have been just three if it weren't for the roster expansion Sakurai made with clones), Brawl has five and this game, so far, has only three (Villager doesn't count due to an Animal Crossing rep being very highly requested pre-Brawl so he was likely added due to popularity). And we're already at twelve newcomers so far, so there's not many more spots left. Even if we were to see two more surprising additions (let's say Mach Rider and Cranky Kong), it'd still be less than Melee (although I really should be saying fifteen since I'm confident in Mewtwo's return). Let's do the math:
64: 1/12 = 8.33%
Melee: 7/14 =
50%
Brawl: 5/18 = 27.78%
SSB 3DS & Wii U (so far): 4/12 = 33.33%
So statistically, we have less than Melee so far. More surprises than Brawl, but it's hardly "full of surprises" that people make it out to be. It's not like they're defying expectations at every moment as well. We're still going to get a balance of expected and surprising additions; it's not suddenly going to slant to the latter this game.
All I can say is, that if people are expecting more characters that "nobody saw coming" I wouldn't count your chickens before they hatch.
I'm not saying it can't happen, but if every single character is somebody "YOU'LL LEARN TO LOVE" then that will probably not be met with overwhelming praise. Likelihood may be a "falsified statistic", but the amount of requests is not. If K.Rool gets passed over for Funky Kong, there will be a lot of butthurt fans. That would be like putting in a minor Pokemon over Mewtwo should we get another newcomer.
If Donkey Kong were a series without a lot of character requests, then it wouldn't be as big a deal. Pokemon at least has a pattern of newest gen Pokemon + Gen One Pokemon. Metroid probably isn't getting anybody, but that could be for whatever reason. K.Rool is for all intensive purposes, the most wanted newcomer for Smash 4. Ignoring that by putting in a different character would be a slap in the face in my opinion.
Again, not saying it can't happen, because it totally can. But I would certainly not expect too many more characters to be "Didn't see them coming" choices.
Glad someone made this post. I don't think DK is in a similar enough situation to where a surprise characters is as likely as it was for Mario or Pokémon. The Mario reps war had no agreements whatsoever and mostly any Pokémon could work in a Smash game as a fighter and Gekkouga worked since there was no true Lucario to the 6th gen (and it's not like we can't like both Gekkouga and Mewtwo in this game). DK on the other hand have two highly wanted characters; one of whom is the most wanted Nintendo newcomer for this game (only beaten by Mega Man and Mewtwo) and the other that was intended to appear in Brawl and just recently seen a return to prominence. It'd be a lot harder to pull off a surprise character in place of King K. Rool and Dixie Kong. Even if it happened; it'd be Cranky Kong, not Funky.