So, I had this idea recently. What if the ARMS character included (whoever it is) has a moveset specifically built around the stretchy arms mechanic, along with interchangeable ARMS, and excludes anything unique to that character? This way, potentially ALL characters could be in as alts, similar to Bowser Jr.
Yes, I know it seems like a travesty not to include any of the individual characters' abilities, especially when they are all so unique. But think about it: the mechanics of ARMS alone is already unique enough to build a character off of. And all the characters could fit into it like a glove, much like they do in their own game. I mean, let's be honest, here: the title of this thread isn't "Spring Man for Smash." Or any specific character. It's for An ARMS character as a concept. if WE have trouble deciding on a solid representative, whether because they're all pretty similar or all have an equal shot, then why would Sakurai think any different?
We have a golden opportunity, here. ARMS could be the first game to have its entire cast in Smash all at once. I can just see Sakurai making a point of that. And much like the Koopalings, we can lament the fact that they don't use any of their unique tricks (and the Koopalings DO have about as many unique abilities per member as ARMS does,) or we can celebrate the fact that every character got in. And for a game where the tagline is "everyone is here!", this would be a perfect fit.
The only problems I can see are that certain heavy characters' builds might not fit with everyone else, and that there are only 8 slots for costumes. One solution is to simply pick the 8 most popular characters (which will generally exclude the heavyweights anyway, sans possibly Mechanica.) Another solution is to create a clone character spot for the heavies, using the same moveset applied to a larger hurtbox and with tweaked stats, which would fix both issues nicely. Either way, it wouldn't be much harder to work around than the Koopalings.
I have a feeling I may get some backlash for this, lol. But honestly, I'd be beyond okay with this setup if it meant I could play as my favorite ARMS characters instead of just Spring Man. And believe me, I'd miss Helix's ability to squash and stretch...but man, it would mean I'd actually get to play him in Smash. And everyone else, too.
To me, that's worth sacrificing what would likely be one unique move.