Yea, it's only if fast falling samus and regular was on one character that I disagree with. Dark or fusion (fusion is the only game she falls fast in, dark samus would be more floaty tbh) as a separate character would be cool.
Special Moves would need a change up.
No bombs, because the full speed mucks up bomb jumping anyway.
Missiles too OP as they are (as i said, SHFF missiles is too good)
Fusion Samus wouldn't have grapple.
Alternatives -
A new angled screw attack, as fast falling + no bomb jumping and grapple gone means new recovery will be needed.
Perhaps one of the moves could be a shine spark (could be like wolfs >b)
Diffusion Missiles instead of charge beam (functions nearly similar to charge beam, except a non charged one is like a homing, semi charged like a super and fully charged is a super that explodes into a spread shot on impact/max range
Something like a speed booster?Or power bombs =D
Aside from fallspeed, though, Fusion Samus isn't particularly different from Samus. Dark Samus could actually get interesting. It could be given float, but also be a fast faller. The thing about Dark Samus in both games where it was actually is that it was blindingly fast, but would have moments where it'd float in place. Short short hops and fast falling would give it speed, and the float could give it that sense of floating with a special of some kind.
Actually, this has me feeling all creative, now.
It would be faster on the ground, with a different run animation, with good momentum install, but poor air control. Its jumpsquat would probably be around 6 frames. All Ice moves would have purple ice, if possible, and leave opponents with the dark effect. Nair, uair, fair and bair would basically be Ice Mode Samus moves, but dair would be a multi-hit phazon beam attack, with aura effect on hit. Nair might come out a frame later. Range might be slightly nerfed overall. Grounded moves would look the same as Ice Mode, but would likely have different knockback, damage and angles. Dsmash wouldn't go behind Samus, utilt could have a hitbox on the rising foot, and not meteor grounded coming down, etc. It would not have a grapple beam, and its throws would be a bit more powerful.
Its specials would be revamped to match its abilities from Echoes. Itscharge beam would fire the short ranged spread beam, and there would be more "beams" the more charged it got. It would have the phazon missiles, but they wouldn't be land cancelable. They would probably do less knockback and maybe even have less range. Instead of bomb, it would have the burst attack it used when Samus shot a missile or got too close. Instead of Screw Attack, it would have the dive bomb attack from Echoes, but going up instead of down.