Using The paladin exploit in Onsal is indeed cheating

[Doozer]

Intervention | Ability
Cast: Instant
Recast: 25s
Effect: Grants Intervention to party member, reducing damage by x% (between 10 and 40% depending on other ideas to add here)
Duration: 8s

Adjustments can be made, but this is a generic template that has been used before and was considered strong and viable without being broken.

That seems fine to me. Something that just gives heavy mit to another player can turn the tide but not guaranteed if the player it was given to squanders it.