I've been a WHM all through XI and I confess I would have been lost without Reraise. I still think it should be restricted to WHM, because it's tactically a better choice than giving it to everyone. Another option is to take a lesson from earlier games and let WHMs cast it on other party members. That way you can cast it on the WHM AND the tank so you have someone to draw aggro while the WHM fixes everything. As long as it's not tied to Sacred Prism, it won't be too broken.