I love pet classes, my favorite was the Minstrel in DAOC.
The Minstrel could charm mobs, even mobs of a higher level, to be pets. You had to keep a song continuously going to keep the pet charmed. If you wanted to do something else too, you had to "twist" your song with the other thing. A mob higher than you could still sometimes break the charm and attack you. This was great fun!
I used to have a blast charming a tree, and then hiding while in a PvP zone with the tree out. Players coming by would sometimes attack the tree, thinking it was a regular mob, and then I'd jump out. AHA!!!

ESO's pets are so limited, it would be great if we could charm nearby mobs to use as pets.