I don't feel as strongly about wanting a character in as I do about not wanting some of these in. I'll go down the list.
1. Pichu - I would ONLY want Pichu in if he was ported exactly the same as Melee. Sandbag character. Don't try to buff him.
2. Black Shadow over Ganon - I'm pretty positive this won't happen, so I'm not going to get into it.
3. Black Shadow/Goroh/Any other F-Zero character - F-Zero does not deserve another representative. Just because a franchise only has one playable character, that does NOT mean they need another. Every F-Zero game combined has sold around 5.8 million units worldwide...that's not very significant as far as Nintendo franchises are concerned. For perspective, Star Fox has sold 11.21 million units, Metroid has sold 17.59, Wario has sold 22.65, Animal Crossing has sold 24.75, Kirby has sold 33.38, Wii Fit has sold 43.98, DK and Zelda have sold over 70, Pokemon has sold 226.07, and Mario has sold...513.85. etc. etc.
Aside from the (lack of) significance of the franchise, none of these characters actually fight in their game, nor are they very popular, nor are they iconic, nor do they likely have fighting voice files that can be used, nor does F-Zero have a new game coming out that needs promoting by adding characters, nor would it be considered a retro franchise (it has somewhat recent games). There is no reason why an F-Zero character should be added if additions are limited.
4. Lyn - Fire Emblem has enough representatives relative to sales/novelty. There are already plenty of standard sword users in PM.
5. Hector - Same as above. An axe wielding character might be cool, but FE is adequately repped.
6. Sukapon - Has the obscure/retro appeal. I would be happy if he was included. Historically interesting to Nintendo even if not necessarily important.
7. Waluigi - I honestly find Waluigi hilarious. I would be happy if he was included as long as he's silly and annoying (in aesthetics, not spammy or campy). I like his design, and I would like to see a Wario Ware outfit version of him.
8. Andy - I'm really a fan of unlikely fighters in Smash, and I think Andy could potentially be a good addition. He's a little on the obscure side, but modern enough where people recognize the franchise. This is one of the few characters that the PMBR could actually just "hire" a voice actor to create sounds for.
9. Sami - Again, Advance Wars is pretty obscure (only having sold 2.3 million units), and it definitely doesn't deserve two characters. If this character is apparently more similar to Snake, I'd say forget it.
10. Ridley - He is already a boss (technically 2) in Brawl. If the PMBR ever gets around to editing the single player modes, I think he should definitely stay in that role and be improved on that front.
11. Dark Samus - PM/Brawl already has 2 takes on Samus, and Samus now has two stances. Aside from that, I think Metroid is fine with only really having Samus as a representative. Any of the hunters would just be based on a random pick, and while fondly remembered and well known, Metroid isn't large enough to the point where it TRULY deserves more reps.
12. Isaac - Despite being a sword user, he seems to have some really interesting potential for other unique moves. The franchise is on a similar level to Advance Wars, so one representative would be nice. Since he was an Assist Trophy (and based on how Sakurai wrote about him on the Dojo), I'd say there is a chance he could be included in Smash 4.
13. Dixie Kong - DK is definitely a very profitable franchise, but I don't think Smash needs Dixie. How different would she really be from Diddy? Do we really want another monkey running around with an even higher pitched voice? I'd say pass on her.
14. King K. Rool - I think he looks stupid as hell, but I'd prefer him over Dixie. Just a personal opinion.
15. Paper mario - I think he would be a very cool addition to Smash, but I feel like he would be a very difficult character to design. He'd be cool, but I'm not sure how "worth it" including him would be.
16. Bowser Jr. - I think Bowser is a very fun character to play (he's very popular as well), so a smaller but speedier version of him would likely be very fun. I wouldn't mind it if he were included.
17. Toad - Peach's B.
18. Saki Amamiya - Similar situation to Isaac and Andy. He'd probably have a fun, up-close, agressive playstyle perfectly suited for the Melee environment.
19. Krystal - Star Fox is adequately represented.
20. Tom Nook - Animal Crossing already has a stage in Brawl, and sales (and Smash 4) definitely indicate that it needs a representative. He is almost certainly not going to make it into Smash 4, and there are enough tools in Animal Crossing that wouldn't require him to be a clone of The Villager. I would like him, but his inclusion might be somewhat problematic depending on just how similar to The Villager he would have to be.
21. Masked Man/Claus - I think Mother is adequately represented. I don't feel strongly about him either way.
22. Tails/Knuckles/Shadow/Silver/Eggman/BigtheCat - NO SONIC CHARACTERS. If PM adds any of these, it will completely sully my perception of the back room. These characters should not even be brought up in BR discussion. Aside from the fact that these characters just simply don't deserve a role in Nintendo's All-Star lineup, third party characters are special guests, and only ONE character from any given third party franchise should be considered for inclusion. That decision should only be made by Sakurai, and the bureaucratic process for building a character based on another company's property is a nightmare in itself. Including 3rd parties into PM, despite the fact that they may exist in some form in Brawl, only exponentially increases the chance of a C&D.
To be frank, the more I think about it, the more I feel that adding a brand new character is just a bad idea. It's not worth the risk for a C&D, and even if a character is included that isn't in Smash 4, it still might be seen as competing. None of the options truly thrill me, and PM already has the most amazing roster of characters in any fighting game imo.