Maybe they're afraid to make the automatons ungimp because pups would be able to solo more efficiently or maybe the creator of the AI doesn't see anything wrong with it.
It's mainly a problem I hinted on earlier. How close to a second player should a pet get before it's too much? As is, there's very little penalty to the player for letting a pet die (Usually just waiting a short bit on a timer, BST having a small gil expense if using jugs). PUP, BST, and DRG can be a strong physical presence without their pet around, so it's not like they're completely useless without.

Things like the pet invulnerabilities were dumb even if they were useful or gave "a time to shine" as it were. Ultimately, it's a juggling act between what the player and pet can do, to which if people want the pet to do more, the player needs to do less. However, seeing how the early days of PUP reflected that and certainly hurt its popularity through poor gear and perhaps an incomplete implementation, perhaps too much focus has been given to both aspects that, while many might not realize the potential now, still doesn't mean it's not there. The moment a pet can completely replace a party member, however, is when things go too far. That's probably the biggest issue plaguing AI tweaks. At what point do things shift from partially inspired choices to outright delayed, conditional commands?