After lurking for a long time I finally decided to make an account to vote!
+1: Ridley - no reason to not have the main villain of metroid
+1: Waluigi - I noticed that he's pretty disliked, but that one PSA of him is cool and he'd fit right in with the rest of the cast.
+1: Andy - I love srpgs, and advance wars would be a neat series to have a character. Not sure how he'd work, but it would be great to see him included.
+1: Claus/MM - I really like the ideas through the thread of a PSI character clone. Didn't play Mother 3, but Earthbound was great and one of my favorites.
+1: Toad - I don't see him ever being in a main smash game, but he could work. I liked the idea on the first post about him being a mario clone, and maybe using other power ups from the series.
1/2: Sukapon - never herd of him before this thread, but he could be cool as a "wtf" character for PM.
1/2: Paper Mario - I played the N64 game it was pretty good, I imagine he'd be a pain to include with the partners but it would be fun, just not sure if they'd take the time to do it.
-1: Saki - This might not be a popular opinion, but I really dislike the character. I'm sure the project M group could do a good job, but I also don't like the type of playstyle I'd see him having.
-1: Dark Samus - Not that it wouldn't work, but I'd much rather have Ridley.
-1: Shadow - Don't like the idea of including him if it's gonna be a sonic clone.