Wow, i can't believe the pet community would troll on DRG. Thats pretty shocking to me. Of course its a pet job. What a ridiculous notion that it is not.
DRG doesn't fit into a pet-centric setup as well as the other pet jobs for party balance, because it does not share hate nearly as much as the other 3 pet jobs. It does so much of its damage on the main, that its going to take hate. If you are in an all pet party and there is a drg... the drg is tanking and you'll probably need some healing from another source... be it automaton, lulush, or a few more /mage. This talk makes me want to brush of my drg a little. I haven't seen Drg in Abyssea at all... Its fun to play, but my lowest level pet job....

Regarding the limit of only having 1 pet... I think the NPC fellows show that this could easily be changed. it looks like 2 pets when I have pet out and NPC fellow out at the same time. I think auto/mob/avatar/wyvern just all fill the same slot. NPC fellow shows that another slot exists and could exist. ironically, the magian trial log seems to occupy the same slot as the NPC fellow.

The only gear I can think of that goes to all the pet jobs exclusively are the herder's subligar and breeder's set (although I think only 1x french smn ever got that set).