It's so stupid seeing this set on very class, mag or stam, with players just cheesing up the annoying body blocking Engine Guardian provides.
Best thing ever is when I engage an enemy player with my 500 Ballista ultimate buffed by Balrogh and instead of unleashing it to the player, I hit the pet.
Well, making engine guardian untargetable as well as other pets would balance the game as well as improve performances without ruining the combat core. ZOS can't do that.
It's pretty simple and it does make sense:
-damaging pets (except Bugged bones) are untargetable
-healing pets (except lazy Mender) are targetable
It's basically a way to have counterplay. Sorcs can generate engine guardian back to back, which means they can endlessly sustain damage/healing/roll dodge in turns, depending on the proc.
We already have enough OP sets in the game that provide no counterplay.
The problem though is Sorc, as it relies on pets. Balancing that can be problematic. Imagine Twilight Matriarch in PvP that is untargettable and for example provides pretty strong heals, but you can do nothing about it...
I hate hitting someone's pet but I think pets like the wardens bear or at least one sorc pet should remain targetable especially the warden since they give up an ultimate for it.