would this be OP?

[Gemina]

The issue is AST is already OP. Having to choose sects is one of the job's few drawbacks, and even then you can still kind of cheat a sect by casting a regen or shield prior to engagement, and then switch to the opposite sect. It's not a huge edge, but one that no other healer has, adding to AST OPness.

I could see something like this if AST needed help, but right now it seriously does not need any help. The only issue AST has right now is solo play because the card gimmick and abilities like Earthly Star seriously lose their flavor here. Jobs like AST need challenging content in order to shine because nearly all their abilities are structured around group play.

[Grimoire-M]

The issue is AST is already OP.

SCH is OP. AST and WHM are competing against one another because of it. AST is the better one between those two, but SCH is the actual problem. The outlier that AST is trying to compete with that it realistically can't. And WHM can't compete with either without a serious overhaul to Lilies and adding the right cooldowns to tighten up the utility gap. You can buff AST's ability to contribute in this manner to help it alongside WHM without majorly impacting its use in SCH/AST comps. At best sometimes Noct AST's shields are used for tank busters while SCH retains AoE shield priority. That's it.

AST/WHM needs the extra regens more than SCH/AST needs the reliable shield.