AMR isn't a terrible tool for most dps spec. For tanks and healers on the other hand its absolute garbage (at least the specs ive put in there as tank/healer) for example, I plugged my Disc priest in the other day out of curiosity and it told me to reforge/gem to the point of having 19k spirit AS DISC. For my hunter and warlock I very rarely disagree with anything AMR tells me to do, and its much easier just to click a button to get as close to the hit/exp caps as possible without wasting 10 minutes at the reforge NPC and wasting gold reforging/restoring items to get that perfect balance that AMR usually gets in about 10 seconds.