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The problem with most eeveelutions is that they perform like the type they're given.
Leafeon is THE Grass type; Swords Dance, shallow physical movepool, leech seed, abilities pertaining to the sun, etc. You're not gonna see one of these things with EQ or Close Combat or U-Turn because it's just Grass.
Same with Glaceon, THE Ice type; High special attack, maybe some other moves it got from Eevee, abilities pertaining to hail and ice, etc. It will never get things it wants like a good electric or ground move because it's just Ice.
Honestly, if Eevee had a more fitting movepool that fit its tendency for adapting to its environment, all eeveelutions would benefit greatly. Give it Thunderbolt, Flamethrower, Dark Pulse, Surf, etc and they would be that much more usable.