I feel like this would go a long way since this is the traditional scholar ability...don't believe me? FfIII, scholars first appeared with the ability peep/scan their main purpose was allowing you to know enemy weaknesses.

I feel like if they cast the spell scan, maybe it can Debuff the enemy so that allies can know its weakness and hit more often for critical hits or some such thing. It can cost an aetherflow stack. It can also be used to lower enemy damage or some such thing.

Alternatively, a trait called scan which simply increases crit chance or whatever could work.

I know some here will argue that scan belongs to blue Mage. You aren't wrong! In fact this skill might work better with them if they ever enter the world of FFXIV. It just belonged to scholar first