Well I read like the first 30 pages of this and then saw it was a thousand pages so I give up. I'm gonna post now.
Alright, here's what I want for SSB4. First of all the obvious stuff. A better stage builder is a must. I was really excited about the stage builder, that was like my most anticipated thing about Brawl, then it sucked and I cried. Needs MORE backgrounds. Many, many more backgrounds, and more scenery. I want to make my stages look pretty.
Get rid of tripping. Sakurai was tripping when he put in tripping.
More varied Final Smashes. And by this I mean that Link and Toon Link should have different Final Smashes. No, the Fox Final Smashes are fine. In fact let's make more landmasters. In fact let's just make every character's final smash a landmaster. Let's have a mode where the characters all get in landmasters and have landmaster fights. And we can call the game Super Smash Bros. 4: Landmaster
Next up is obviously reverse all the stuff they did to make Brawl's gameplay inferior to Melee's. Melee is much funner than Brawl. Brawl feels weird.
Now for stages: They need to bring back Termina: Great Bay from Melee. That was like my favorite stage, ever. When I found out that wasn't in Brawl I was on suicide watch for a few months. We also need the 64 stages back, mainly Hyrule Castle and Saffron City. And we need more new stages. More Zelda stages. Better Zelda stages. None of this hey I'm a huge flat bridge with a guy on a rhino crap. We need a Lost Woods stage. They need to make a Lost Woods stage. Yes.
Characters: Lots more new characters. Final roster should be 50 - 65 characters. More third parties. Anti-third party people are just being silly. Ninty is running out of fun new characters and third parties enhance the experience. Granted the third parties should fit in with the rest of the smash bros atmosphere (which means no Master Chief and no Sephiroth). I think we should have around 10 third parties in the next game.
High priority:
Megaman, Tails/Knuckles/Shadow, Geno, Ridley, Waluigi, Mewtwo.
Megaman is awesome. He fits in perfectly with the rest of the roster. We need Megaman. We also need another Sonic character or two. Tails would be great because I have always wanted to beat the crap out of Tails. Knuckles would have a great moveset. Shadow for the same reason as Tails. I don't see Shadow as being a Sonic clone though, he has chaos moves, and also he has a gun and a motorcycle. I'm just joking on the last part, please don't flame me. Geno would be a great, unique character. I've never played a Metroid game but Metroid needs more rep and Ridley looks pretty awesome, I don't think size is n issue. Forget you Waluigi haters, I want to have Mario and Luigi vs Wario and Waluigi fights. Mewtwo is the only Pokemon that I care about.
Medium priority:
Dixie Kong, K. Rool, Black Shadow, Samurai Goroh, Knuckle Joe, Krystal, Viewtiful Joe, Bomberman.
DK series deserves more rep. Dixie Kong is a great character. None of this Dixie Kong and Diddy Kong in the same character stuff either, it'd be cool to have them on an actual team though. Dixie Kong could fly the way she does in Donkey Kong Country by twirling her hair or whatever. K. Rool is another big bad guy. I've never played an F Zero game either but Samurai G oroh and Black Shadow both seem like interesting characters and Falcon has been around since the first game, I don't think 3 characters is out of the question for F-Zero. Knuckle Joe would just be cool but I'm not all that concerned about him, Krystal just for more female rep and because of her staff. Viewtiful Joe because he's awesome and unique. Bomberman because he's Bomberman, man.
Low priority:
Birdo, Paula, Midna, Skull Kid, Mask Link, Lyndis, Isaac, Pacman, Bowser Jr.
Birdo I don't think would end up being a Yoshi clone. She could be heavier, she can spit eggs. I don't know. I just don't think she'd be a clone. Paula to replace Lucas for the Mother series. Lucas is lame, I don't like Lucas. Midna, yeah. More variety in the Zelda characters, not just more versions of Link. Toon Link is bad enough, Toon Link AND Toon Zelda would be sad. Skull Kid because I love Majora's Mask. Mask Link just to find some way of making Fierce Diety Link, the most awesome thing ever, playable. Lyndis because female rep fire emblem blah blah blah. Isaac because people are in love with him. Pacman because his Final Smash is obvious and awesome, and because we could have a cool pacman arcade stage. Bowser Jr. has moveset potential.
Characters that I would love to be in but never will:
NiGHTS, Banjo & Kazooie, Master Higgins.
NiGHTS would be epic. Banjo & Kazooie debuted on a Nintendo system and they fit in with the rest of the cast pretty well. Master Higgins because I like dreaming. He was the main character in the Adventure Island series, which if I remember correctly had 3 titles on the NES and 2 on the SNES. I only played the SNES ones but they were great, and he's a great character.