I think there is actually a way to fix OGCDs being so predominant while also not removing them.

Make the basic GCD heals like Medica or Succor completely MP free, so the only cost would be your GCD. Then add MP costs to every currently free tool, from Afflatus Rapture to Pneuma, with the strongest tools costing the most MP.

With that kind of design, while not forced to use GCD heals, you'd want to opt into using them to conserve MP for when you actually need your strong OGCD tools. It also wouldn't harm the less experienced players because they mostly GCD heal anyway.