I think the pet control modes work in a better way. At the moment there are 4 modes for pet control:

1. Stay still, but defend (the pet itself)
2. Follow mode, no combat at all
3. Guard mode, attacks player attacker
4. Assist mode, attacks the same target the player attacks. Plus a bit of # 3 (roughly speaking, I realize there may be some sort of decision weightings in place here assist vs guard)

1 & 2 work well and are as described.

For mode 2 however, if you are using Animal Handling, and use an attack command such as sic'em or clever trick, the mode will get changed from follow, to Guard mode. I think it might be better to be put into Assist mode. The reason becomes clearer below. And especially since you have just told your pet to assist you with said target.

4. In assist mode, whereby the pet will attack what you are attacking, more or less, and for sure if you are not already in combat. The trouble is that this mode also includes implicitly the behavior of mode #3 . So if you ever get attacked (projectile mobs especially), the pet will run up an attack the aggressor, which, in my way of playing is rather a hindrance and think it may be much better that the pets don't have this guard aspect at all in this mode, and simply attack what the player is attacking (if anything of course - e.g. last player attacked mob, if not dead, if dead, then last attacked becomes none).

At the moment modes 3 & 4 are very similar, and nearly identical when you face a projectile adversary, in that when you attack an enemy, the enemy will projectile attack back, so in both modes the effect is nearly the same. This is not the case with melee enemies, as they must run up to you and hit you first to make your pets retaliate, but it's not a gigantic difference.

That's is the crux of it. Pets retaliating while in assist mode is the only remaining egregious control deficiency as I see it. I don't bother with guard mode much at all at the moment since assist mode covers the same scenarios, but having an assist mode that does not retaliate on the players behalf would be much better I think in terms of pet control, especially when part of a group in a dungeon.

I dare say that if you wanted to go mad about things you could make the modes toggle, and additive, so you could set any or all of 1, 2, 3, 4 independently, but that might be difficult to use.