EDIT: See, even you have five new series added. Though Little Mac most likely won't count as a retro, especially since Sakurai said the retro he's thinking of has yet to be "revived", unlike Little Mac.
Also, Lucas isn't going to be cut. Chances are Wolf won't be either.
Yes, I added these characters under the assumption that the roster will expand to 40 and that Mario, Pokemon, and Zelda will not get 5th slots. The point I'm making is that for each 5th slot these series receive the chances of other characters such as Isaac, Shulk, and many other potential characters/series are hampered which in turn would make me sad.
As far as cuts go I would definitely like to hear opinions as my current roster of 40 is also balanced around who is getting cut/replaced. In my opinion it would be very unlikely if no cuts and only replacements were made. The decision of who I personally cut from the list is based on:
Characters who have appeared in two or more games are permanent.
Clones have higher chances to get cut though unique characters are still in some danger. (Take Mewtwo for example)
This leaves Olimar, ROB, Lucas, Snake, Sonic, Pit, Lucario, Pokemon Trainer, Wolf, Wario, Diddy Kong, Toon Link, Ike, Metaknight, and King Dedede.
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Olimar: He's one of the newest original IPs that made it into Brawl. He's safe.
ROB: I feel like he was well received, he is also unique in his moveset and that he's a robot. Safe.
Snake: Super Smash has its own sort of goofiness that everyone can appreciate. Snake definitely contributed to that in a healthy way via his codecs and how he was introduced in the trailer. I want to say he is safe.
Sonic: Least likely to get cut in my opinion as he was the most demanded character for Brawl.
Pit: With the new Kid Icarus: Uprising he's not going anywhere.
Wario: Popular, well received, and fits in Smash perfectly. Safe.
Diddy Kong: Definitely helped the under-represented Donkey Kong series, even with the inclusion of King. K. Rool I feel that Diddy Kong wouldn't 'over-represent' the series.
Ike: He's been the main protagonist in the newest console-based Fire Emblem games. I was honestly pissed when I heard Roy was cut but honestly after some warming up I like Ike better. Safe.
Metaknight and King Dedede: For the same reasons as Wario I feel that they are safe.
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Lucario: He has a chance to be replaced by Mewtwo or a 5th gen Pokemon though I would give it to the latter.
Pokemon Trainer: I feel that him and his Pokemon could use some adjustments. First of all I think we should have the option of switching between a male or female Pokemon Trainer. With strong personal bias I feel that generations 2-4 need some form of representation on the roster. (Piplup, Bayleef, Blaziken) Probably won't happen but hey, I can hope right
Toon Link: Toon Link made it in due to the popularity of Wind Waker. (Don't know how much Phantom Hourglass contributed to that but oh well.) Afterwards he's only appeared in Spirit Tracks. Time to let this guy go just like the last Link clone unless Nintendo pops up with another successful game featuring him.
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Then there's Wolf and Lucas whom I've already stated my reasons for either including or removing. So I guess my next question: is are there going to even be any cuts to the Brawl roster, and if so who would it be and why?