Literally...
In trying out the sorcerer last beta, I found it to be pretty capable, but one thing irked me over and over, and it was pretty much instant. At first, I was baffled, confused, figured I may have missed something (which I still think and hope I did), then became increasingly frustrated...
Where are the abilities to command a pet? There should be obvious ones: Attack, Stay, Come Here being the most blatantly apparent ones... and there are really GOOD reasons for having these, not just 'because every other game has those commands for pets!' Single player games don't need them, they have save points, are way more forgiving, are single player, etc etc... but MMO environment NEEDS them, or else you are letting this extra bit of AI wander around freely doing its own thing.
Several times in past MMO's I have seen guilds/raids give a mandate of "No Summons/Hirelings/Pets/Mercs" type thing, and that was in games where they HAD commands, and the reasons ranged from : 'confused the fight by making the NPC jerk around destroying aggro-control' to 'aggroing random enemies and bringing them to the party' to 'bad pathing caused it to accidentally aggro the entire tower and bring 50 enemies on top of us!!'
AI is never perfect, I don't ask it to be... but that is why we have extra protection against it. Those commands ARE the protections. Yes, it also allows more precise control allowing specific strategies, but that's part of the game as well. Several times (and I only made it to 5th lvl with my sorc due to this) my pet 'disappeared' down the beach SOMEWHERE... had no idea if he was alive, dead, fighting, taking a vacation from a mean and demanding master, dunno... but at least a few times I would stand there looking around in circles (not moving) and a monster would appear down the beach and start charging me... why? because my pet somehow thought that guy was a danger and charged off after him... even though he was WAY away from me. Then when my pet died, that enemy came after ME. So, apparently, the AI has not progressed all that well in some respects.
Another case, I made an archer/summoner... but found my pet would only charge the enemy AFTER I shot it... no command to attack... if there are commands somewhere, let me know, I would sacrifice a slot on my bar for an attack command... So, I ended up tanking every fight that an enemy made it to me, due to no commands...
I think ESO could REALLY use having pet commands, not just for the extra strategy, but also to help keep pets from causing 'other' problems that NEED to not happen...