Unless I'm mistaken most bosses, cosmics, etc are generally immune to or have highly decreased duration against all of the things that allow sentinel mastery to proc. Yet I see healer builds frequently seem to rely on it. I may be mistaken, yet iirc, if these effects can't affect these NPCs then they don't even appear as debuffs on them which means that sentinel mastery can't be procced because allies can't strike the affected target because there is no target that's affected against these types of npcs. With this in mind it seems to me that sentinel mastery would only be useful against trash mobs as they're the only ones these effects can be applied to.
These healer builds are supposed to be "end game," which means healing for super-bosses like cosmics and the like but they talk about sentinel mastery quite a bit so I'm just wondering if this is one of those things that's just supposed to make getting to the boss easier or.. what.. exactly is going on with recommending Sentinel Mastery.
Either I'm wrong or I'm missing why Sentinel Mastery is chosen for so many builds in that healer thread, either way if someone has the time I'd really appreciate some clarification as to why that's what's suggested. Either I'm wrong an an idjit or I'm right and not seeing something.