I think this has to be a blow struck due to Ret's current arena representation in 3's, and seems a bit much for Holy which is far from mobile and needs the group utility to be competitive. 10 secs apparently may still be too long, so expect yet another nerf later (or something of a side-effect, such as a slow after you come out of Freedom or a Forbearance-like debuff lasting longer than 25secs).