Although it's unlikely, I support assist trophies. We got a mook. We got a non-protagonist before a protagonist. We got a rep from Nintendo's CURRENT rival. Some of the most essential characters are assist trophies and I don't think they should be rejected just because they're assist trophies. Here are the assist trophies I want to see promoted to fighter the most...
Waluigi: I want Waluigi for completion reasons. We got Mario, Luigi, and Wario. Waluigi would complete the Charles Quartette. People forcing me to not want him and claiming I only want him "for the memes" only makes me want him even more.
Move set: Tennis shot (neutral special), Zipper motorbike (forward special), Corkscrew (up special), "WAH!" (down special), Showtime tennis shot (final smash).
Costumes: Purple & black, Yellow & purple, Green & blue, Red & blue, Tennis aces, Yellow Tennis aces, Green Tennis aces, and Red Tennis aces.
Acceptable substitutes: None.
Zero: It's only a matter of time before we get another Sonic rep. I don't want another Smash bros with more Sonic reps than Mega Man reps. And as much as I would like to see Proto Man or Roll join the fight, I think two third party reps per franchise are enough. Zero is a Mega Man character who has his own series and isn't a Mega Man.
Move set: His move set from Mega Man X4 with Zero legends as a final smash where he summons Zero from Mega Man Zero and Mega Man Model ZX for a team attack.
Costumes: Shoulder pads, Black armor, MMZ colors, Zero nightmare, Armor X colors, Axl colors, Bass colors, and Vile MKIII colors.
Acceptable substitutes: Any Mega Man character.
Krystal: It's about time we got another Starfox rep. I don't want Wolf to be the last Starfox rep. And as much as I would like Slippy, I think Krystal would make more people happy.
Move set: She could be a semi-clone of Fox with her Spear used for forward attacks.
Costumes: Unsure.
Acceptable substitutes: Any Starfox rep.
Springman: I want Springman for obvious reasons. Though I think it's unlikely that we would have two ARMs reps as DLC for the Fighters pass vol.2. Maybe next time.
Move set: A clone of Min Min where he uses his standard arms for his down special, and uses Rush for his final smash.
Costumes: His basic design, his palette swaps from ARMs, Springtron's colors, and Springtron's palette swaps colors form ARMs.
Acceptable substitutes: We already have an ARMs rep.
Honorable mention...
Akira: Although I don't want any more Sega reps in Smash (especially another Sonic rep), I'll make an exception for Akira. He is Sega's main representative in Project X Zone.
Move set: I'm not sure, but his Forward throw could be Tetsuzanko and his final smash could be Hougeki Unshin.
Costumes: Half of his costumes could be his design from Project X Zone while the other half could be his polygon design.