>Barrage
Change it to a Special Attack because Exeggutor, the only pokemon who learns it, is a special attacker. Raise power to 25, make it 100% accurate. There, now it's a special normal type Bullet Seed. Still almost useless, but now it's not complete ass.
>Confide
Now it lowers SpA 2 stages instead of 1. Being outclassed by Mystical Fire (same thing but with fire damage) is not a good place to be.
>Egg Bomb
Change it to a Special Move. Exeggutor is a Special Attacker, after all, and dumbasses can use it on Offensive Blissey (still terrible, but it would be more fun). Sad when the only two pokemon that learn it are special attackers.
>Terrain Moves
Electrical, Grassy, etc.
Make them permanent instead of only 5 turns.
>Heal Block
Lasts until opponent switches out instead of a mere 5 turns. Also it should be a Special Psychic Damage move with 60 Base Power.
>Lucky Chant
Heals 30% of user's health bar. Using it in succession adds 5 more turns to the crit immunity. They're cumulative.
>Magic Room
Instead of suppressing items for 5 turns, everyone drops their item when the Magic Room goes up and anyone switching in to the Magic Room drops their item as well.
>Mist
Instead of keeping user's stats from changing, it prevents ALL pokemon on the field's stats from changing, that way you stop boosting.
>Poison Gas
Raise Accuracy to 100. Using it on somebody already poisoned switches it to Toxic Poison.
>Psywave
Just make it a Psychic type Seismic Toss
>Quash
Add +1 Priority and 40 Base Power physical Dark Damage. Now it's a Dark Type Quick Attack that makes things screwy in Doubles.
>Rototiller
Add 60 Base Power Physical Ground Damage. Hits all enemies, still raises your team's Attack and Special Attack. Raises stats 2 stages in Grassy Terrain. Also, give the move to Torterra so an actual Grass type can use it to boost itself.