I doubt that AST rework is linked to a new caster. As a number of people of pointed out, SE had a backlash related to DPS changes which they likely didn't predict. This coupled with their having no dedicated healer designer as well as having prior issues with AST rework likely made them rework some changes.

I very much doubt that that incorporated some dramatic changes to their AST rework, as Deo14 pointed out they still likely botched it, but perhaps it will not be as bad as what Deo14 is painting.