There's also no reason they cant make a tine mage healer. Them saying it would be unfeasible to let you actually stop time is ridiculous.
Of course that's infeasible. But you dont need it to do that. All you need is a thematic spell kit that isnt identical to whm or sch. And also give up on the stupid idea of shield healers vs pure healers.

Regens can be based on accelerating healing, it could be very regen focused. Give it a dot kit for damage that everyone still misses from old summoner. Big heals could be based on reversing the last instance of damage taken. And the support spell possibilities are endless.