I think that Raid should have a more or less standard set of alternative mechanics.

What are the most exploitable mechanics for Raid manipulation currently?

Turn Meter manipulation.

I have a beefy Teebo under my wing, and working on other TM helpers as well. But they are broken-op in Raid. What I think would go a long way to make things more balanced in Raid mechanics would be unpopular, since it qualifies as a nerf, but it would be specific to Raids. Not anywhere else in the game.

The core rule would be that friendly TM buffs would be half as powerful. Thus, a +40% TM becomes +20%.

For enemies it would depend on type.

I am classifying Raid enemies in 3 classes:

Raid minion (Gamorrean Captain summoned minions)
Raid Elite (demiboss - Gamorrean Captain)
Raid Boss (Boss - Rancor)

Raid Minions - suffer TM manipulation effects normally.
Raid Elite - TM debuffs are at 75% power.
Raid boss - TM debuffs are at 50% power.

TM would still be a thing in Raids, but no longer be this thing so powerful you can solo a Raid with a single team.

I feel this is necessary because we need more player participation before the Raid is over, the internal strife/competition for the top score generates a bad attrition and the TM gods are eating up too much opportunity for participation and teamwork.