While all these new characters and stages are being revealed, there's still no info on pokemon and assist trophies(or any items for that matter). What new pokemon/assist trophies do you want in the new smash bros?
What Eevee should do when sent out: Depending on the enviroment it evolves into an Eeveelution.
Eevee: Normal and plain stages like pokemon stadium without changing. It'd simply use tackle if it doesn't evolve.
Vaporeon: Water based/themed stages especially those like Delfino plaza. It'd attack with Surf or Hydro pump.
Jolteon: Electricity based/themed stages (probably The electric field from pokemon stadium or Mega man's stage). It'd attack with a stronger variation of thunder or use charge beam/volt switch.
Flareon: Fire based/themed stages like Pyrosphere (or whatever the new stage from metroid was called) It'd attack with Flamethrower or Fire Blast.
Umbreon: Dark based/themed stages or probably stages where the stage's background changes from Day to Night ( Like Villager's stage). It'd use faint attack or dark pulse.
Espeon: Light based/themed stages (like the heaven stage where pit resides in would be ideal to consider as a light based stage) or probably stages where the stage's background changes from Day to Night ( Like Villager's stage). It'd use Psychic or Psyshock.
Leafeon: Nature based/themed stages like DK jungle. It'd use Leaf blade or Solar beam.
Glaceon: Ice themed stages like Ice climber's stages. It'd use Icy beam, Blizzard or Ice shard.
Sylveon: unknown, it'd probably evolve in a kirby stage. It'd use Moonblast.
I like the idea, a lot. Although, I wonder if they can do the coding that will allow Eevee to evolve depending on the stage. I'm assuming they can. But like those stages that change will be tad bit difficult.