Honestly? Take Tier II enfeebles out of Merit Category 2 and allow us to learn the spells with scrolls.

Let the merits increase potency/accuracy, or unlock AOE versions of existing spells.

Buffs like Brave (ATK+ACC up), Faith (MATK+MACC up) and Debuffs like Wait (a short-term Amnesia) or Confuse would be an interesting concept.

Ultimately, if RDM is going to have spells like Temper, they shouldn't be self-cast only.
Or, Merit Category 3 should allow us to unlock AOE versions. (Temper, Enspell, Haste, Refresh, Phalanx, for example).