Finally have some descriptions, some may be off due to my big headache just to make this:
Best NES Retro Reps:
Takamaru: Probably the most obvious rep, has been given some extra popularity since the minigame of Nintendoland. I think this character would be the best obscure Retro rep to fit into Smash.
Balloon Fighter: He obviously has the same reason as Takamaru, but I think it’s finally the time to make him a character, given the fact there was a pirahna in an Ice Climbers stage in Brawl. Personally, to me, that’s a big hint with many of his references in many other Nintendo games (notably Warioware).
Best Gameboy Retro Rep:
Prince Sable: I think if Nintendo were to decide of a Gameboy rep, Sakurai would choose Prince Sable. Prince Sable is part of an amazing game called “For The Frog The Bell Tolls”, which was unfortunately was a Japanese exclusive Gameboy game. The game had a story with themes similar to Earthbound, it had unique gameplay being similar to Zelda. If Sakurai were to add him, he would have to get Prince Sable’s character, description, and personality right to tell people, his inclusion was worth it and maybe worth it for a revival.
Best Additional KI:U Reps:
Palutena + Dark Pit + Hades: The only reason I combined these guys together is because there are lots of interesting characters in KI:U (In which Sakurai made) that could make it to Smash 4. Palutena is a shoe in, but Dark Pit and Hades have a little extra reason. Because Sakurai had the interest to add new awesome KI characters into the franchise, and the fact there won’t be a sequel to KI:U (Like Sakurai saying there won’t be a sequel to KI:U for a long time), I think it’s a perfect time to showcase these new characters in action.
Best Additional Metroid Rep:
Ridley: This character is surprisingly the most requested Nintendo character for Smash. I’m actually surprised Sakurai hasn’t give an extra bump for the (popular) Metroid franchise. Ridley fits perfectly into Smash, the only way for him to get in is if Sakurai listens to it’s fans.
Best New RPG Rep:
Shulk: Again, I don’t have much knowledge about Xenoblade, but I think he’s a better choice for an RPG rep than Isaac. I think it’s Shulk’s time to be in the game, because he would be identified as ignored for years if he wasn’t in Smash. Xenoblade Chronicles is the only game Shulk appears in, it’s that time to use.
Best currently popular Rep:
Little Mac: Since the revival of Punch-Out, the popularity of Mac has grown. I think Sakurai can finally make this guy a character, he is no longer obscure to anyone. I don’t really have much to say though, I don’t know much about Punch Out! either.
Tom Nook: I think it’s finally the time Animal Crossing got a rep for Smash. The popularity is noticeably huge, I think many people would be interested in Tom Nook as a playable character, to me he has more personality than a dang regular villager. I would imagine he would have a pretty silly moveset.
Best Additional Pokemon Rep:
N: I still think N could make this one. What did this trainer accomplish? The first rival to ever own a Legendary Pokemon, being a major part of the plot of Pokemon Black/White, and a unique graceful personality (Watch the current Pokemon anime to find out what I mean). His Pokemon could range differently with different generation Pokemon, but the first Pokemon he would use is obviously Zoroark, and personally the other 2 Pokemon could be Carracosta and Archeops. But, I could alway replace N with Blue (Gary Oak) for being the first rival of Pokemon, I would go either way.
Mewtwo: I think Mewtwo is a great choice, it would represent a big return for Mewtwo with his new form (Which could be a final Smash). He sadly would replace Lucario as a sacrifice.
Best Additional Fire Emblem Rep:
Chrom: I really don’t know much about FE, but all I can say is that if Nintendo and Sakurai had to agree on what FE character is currently best representing the franchise, it would be Chrom.
Best Addition DKC Reps:
King K. Rool + Dixie Kong: I’m questioning why the DKC doesn’t have enough reps. I think Dixie Kong and King K. Rool would fit perfectly into Smash. The only reason they would both have to be playable in Smash is because logically something is missing that represents the whole entire DKC series despite being the 4th best selling Nintendo franchise (Dixie representing DKC3 and King K. Rool representing the villain of DKC series).
Best Additional Earthbound Rep:
Ninten: Going with the idea that all heros of a franchise should be represented, I think Ninten is the perfect choice as the last Mother rep. I’m sure Sakurai can make Ninten (in terms of looks and moveset) different to make Ninten awesome as Ness. Plus, most of the Mother music the Smash series gets is based on the many songs of Mother 1 and Mother is also the top 10 NES games according to Famicom. Of course, Porky can be in instead of Ninten to represent the best of Mother.
Best Additional Historical Rep:
Nester: The historical rep can be anyone, but if there was one historic rep that could define obscurity (like R.O.B.) and help live on the life of Nintendo Power, it would be Nester. This guy was part of a magazine that was a player’s guide for every-gamer in the 1980s. I think he would get in if Sakurai did some wholesome research on Nintendo everywhere.
Best Additional Starfox Rep:
Krystal: Being different from other Starfox reps, Krystal fits perfectly into Smash for a fourth rep of the popular Starfox series. The only way she can get in is if a Starfox game (involving her) were to be developed.
Best 3rd Parties:
Bayonetta: This probably is not personally my opinion and my choice, but if I were to add the partnership between Sega and Nintendo, and combine that with recentness, it would be Bayonetta.
Goku: Please do not go nuts, just let me explain this one. Goku is the most popular and powerful (manga/anime) character of all time. With Namco Bandai working on the next Smash (Who owns the videogame rights to the Dragonball franchise), it might be actually possible for Goku to join Smash. The only step Goku has to go through is whether Sakurai decides to let off his criteria on a Non-Nintendo (videogame) character.
Megaman: This character is one of the most requested 3rd party characters for Smash 4. The support comes from both the interest of Capcom and the amount of games in Nintendo systems Megaman has been in. I’m not going to say much, but I think Megaman would represent a partnership between Capcom and Nintendo.