Which characters? If you can't make a case for the entire roster then the mode is flawed.
I can make a case for all of the currently revealed characters
General: better ground dash
Greninja: Fast, counter, teleport, projectiles
Charizard: Multiple jumps, heavy (last longer), projectile, flaming dash attack
Yoshi: one of the best jumps, aimable projectile
Sheik: Fast, teleport, two projectiles
ZSS: Projectile, ranged melee weapon, a kick that reflects, long range grab
Diddy: Bananas, projectile
Lucario: Projectile, force palm, counter, extreme speed (al get stronger at higher damage)
Little Mac: super armor, moves with projectile invincibility, low profile while running, fast
Dedede: gordos, heavy, hammer has great range
Zelda: Teleport, reflector, djins fire, knight projectile
Marth: Fast, Counter
Rosalina: Ranged Melee, projectiles, deflector(down B cancels projectiles)
Sonic: Extremely Fast, great mobility
Toon Link: Bombs, arrow, sheild, grounded up B reflects, long range grab
Peach: Projectiles, Floats
Luigi: Projectiles that cover a good area, scuttle can go under some projectiles
Olimar: Projectiles that can act as shields and get stronger over time (5 variations)
Mario: Fireball, cape
Villager: Pocket, Bowling ball, tree
Donkey Kong: Heavy, armored specials, foward smash is good for nullifying projectiles
Link: same as toon link
Samus: Charge Shot, missiles, bombs(down B), long ranged grab
Megaman: fifty bajillion projectiles....give or take a few
Wii Fit trainer: Sun Salutation, Volley ball, ability to power up moves(deep breathing) which includes her projectiles
Kirby: multiple jumps, final cutter has projectile, down b grants form of invincibility, can absorb neutral b projectile/anti-projectile powers, can duck under most projectiles
Fox: blaster, reflector, fast
Pikachu: small profile, two projectiles, fast
Bowser: Heavy, Projectile, faster than previous versions
Pit: Reflector, projectiles
Key words, Seem to.
From what i've seen, characters Marth has had little changes to his moveset, which will give him a major advantage on FD.
There's also the fact that no matter how many flashy kicks and jumps you add onto characters, they will always be at a disadvantage to zoning characters like Megaman and Falco on FD, due to lack of projectiles.
Not necessarily true. The Lack of projectiles is fine as long as the characters have a viable way of dealing with them: reflectors, deflectors, counters, telleports, speed, mobility, super armor, absorbers, far reaching attacks/grabs, etc.
Just look at your example, Marth. He does Just fine against projectile users. And need I remid everyone of the Jiggs/Star Critter matchup?