I feel a return of Quickened Aetherflow and possibly gaining 1K MP with Dissipation (since you technically just refilled stacks as if you used the Aetherflow ability itself) could help with the MP management issues.
Printable View
So far from the Live Letter we know for class changes there will be no nerfs, some slight buffs (numbers related to SCH, DRG, BRD) and Monk stuff.
From that it would seem 5.4 healer changes will be a slight potency buff to SCH (could be to heals or damage) and nothing else for AST/WHM or general QoL.