So I not sure if this had been brought up before but I've had the idea of removing energy for a custom campaign I've been planning on. Instead all abilities will run on a cooldown and cloaking would be turned into a mode that the player can trigger on or off at the cost of that unit not being able to attack while cloaked.
I'm working on making a map so that people can test out the effected units. But first I'll just throw out here my planned changes.
-Defilers: Dark Swarm and Plague on a cooldown and add Consume but it deals 100 damage to target unit and heals the Defiler 50 health.
-Queen (Classic): Parasite, Ensnare, Spawn Broodling and Contaminate and the Queen requires a Lair to unlock.
-Overlord gets Detect back and gains Spawn Creep Tumor. Unlocks Mutate Ventral Sacs with a Lair.
-Sentry: Keeps Guardian Shield and Force Field but gets Graviton Beam as an unlockable power from the Cybernetics Core.
-High Templar: Psionic Storm, Hallucination and Feedback but it does 100 damage to a single target.
-Dark Templar: Bend Light, which lets Dark Templar cloak but can't attack while it's active and Void Stasis. DT is unlocked with Templar Archive.
-Observer: Can decloak to pull enemy units.
-Arbiter: Increase basic attack to 15 +15 vs Armored per second. Keeps only Stasis and Recall.
-Medic: Heals at a rate on 1 per secound.
-Ghost: Cloaking like with the DT is permanent but while on, Ghosts can't preform basic attacks. Snipe is on a cooldown so is EMP Round is a stun for mechanical units.
-Wraith: Like ghosts can't attack while cloaked but will probably have an extra ablility, though haven't picked one out yet.
-Medivac will be converted into a regular dropship with Rapid Deployment or Detection.
-Viking will be reworked into a Valerie replacement with splash damage anti-air basic attack and the Seeker Missile ability on cooldoown.
-Science Vessel: Detector, Nano Repair ( Like Medic 1 per secound.), Irradiate and Defense Matrix on cooldown. Requires Fusion Core
-Battlecruiser: Like they've already done in multiplayer, turn Yamato Cannon into a cooldown ability.