What if the Pokemon started out in their first evolutionary state, and they all grow from there?
....But I can only see this working with ONE pokemon. Keeping track of THREE pokemon, and evolving them, is too much to handle in short, 3-stock matches. (Or the Sakurai favorite, 2-minute matches).
Been spreading this idea around for a while. Good to see someone else think of it.
This wouldn't be for just one Pokemon though. I'd picture it'd work for all evolution lines of the starters from the first generation. But you could pick them on the Character Select Screen like selecting which Pokemon you'd wanna start with, or picking Zelda / Sheik. Except this time you choose Grass, Fire or Water as your theme / starter.
And even in Time matches it could work, as you'd evolve after taking a stock or 2 or something. No reason for it not to work like that in Time. It's really the time thing, and could work very well.
This would make all Pokemon from the Trainer worthy of being called their own character, and even adds to their uniqueness. If you think about it, not much has to be done for Ivysaur to behave as Bulbasaur or Venusaur. So that's an easy one. Next, Charizard is already pretty ground-based, and not too aerial based, so they could revamp Zard himself, and base his pre-evos on the more ground-based style, minus wing attacks ofcoarse. Squirtle could be made a bit more defence-orrientated by making his Widraw an actual defensive move, that'd block damage, a little (like, 15% super armor) so evolving up to the uber tank Blastoise wouldn't look all that weird.
Of coarse a few moves could be changed up upon evolution as well, or the special and normal moves simply would get stronger with only a few changes at the final forms?
For example, Charmander and Charmeleon shoot Ember for B, and recovery is Fire Spin (basically Zard's Up B) while Charizard actually shoots Flamethrower, and uses Fly as Up B (which'd perhaps work more like Pit's Up B this time and allow his to breath fire when flying).
Blastoise's difference with Squirtle and Wartortle is of coarse the ability to shoot out of his pumps, so perhaps Squirtle would start with Water Gun as an attack, then Wartortle uses Bubble Beam, and Blastoise Hyrdo Pump.
Hyrdo Pump would be a natural counter to Charizard's aerial approach, as it'd combine the effect of Water Gun (pushing away) and his Pokeball attacks in Melee and 64. Keeping Zard grounded. Meanwhile, Blastoise has poorer range on his regular attacks, which'd make him a natural prey for Venusaur's long grabs and Vine Whip / Razor Leaf combos. Venusaur's Down B should also be somewhat like his Earthquake attack from Melee, so that Charizard again has the advantage when approaching from the air.
Combine this also with the inbuild elemental system of Brawl's Pokemon Trainer and I think this'd be the best revamp possible for a character. Better yet, this would only be one character on the select screen, and would be one of the more unique ways to add in clones on a practical way.
Also like the prospect of doing this with Pichu / Pikachu / Raichu, but that could be overkill to have so many Pokemon around. Yet... It'd be such an awesome reference to Yellow, the 2nd gen, and possible Pikachu's N64 Smash moveset through Raichu. And of coarse Pikachu would sitll be selectable himself.
Just giving voice to my ideas again. Since you brought it up and all.
As for Sudden Death: You'll control the character you last used in battle. 1 stock matches: start with the second evolution to balance everything out better. Or start with the last, choice of how balanced everything is.