In compensation, the shields are much beefier, Like, a 1000/750 potency heal-sized shield for single-target and AoE, respectively, along with having a .5s cast time. If the shield breaks, the target receives a 450/300 potency heal respectively. If the duration of the shield runs out, they instead receive a 300/200 potency heal instead.
The idea would be to make it so that shield healers should more rely on preventing the damage, rather than reacting to damage. The quick cast time allows for reactionary shielding, so that you can get the shield up before the buster/raidwide goes off. The Excog-like effect is to allow for healing if damage is not fully prevented from the attack, or to patch people up if damage was not blocked to begin with. A breaking shield healing more is to patch up those that took damage beyond the shield, while the duration running out heals less since the healing may not have been necessary.
I imagine such a change would require a change to Emergency Tactics for Scholar, along with a similar ability for Sage. Likely make it so that, for 10 seconds, all shields instead provide their broken shield potency heal, to allow parties running Sage and Scholar to handle heal-to-full mechanics.