There are two problems with that – 1: taking a perk only to be able to fight a single enemy type shows how otherwise useless this perk is. 2: if I have to take Fortified Mind to be able to use any tactic against that particular enemy (other than “try to stab them with a spear and pray), then it shows that I am out of options. No other enemy present such a problem.
Currently there are only like five main enemy types: So if a Perk completely makes one of those types a walkover, it’s hardly useless. And devs have indicated there will be more enemy types where this Perk is needed. Moreover, as I’ve said, you don’t need to slap this Perk on everyone: Do it just on a few tanks, and that’s sufficient. And I say tanks, because after Rotation and perhaps Brawny, you could go in a lot of directions as far as T2 Perks are concerned on a tank. So it’s not like you’ve got something clearly superior you’d need anyways (which would be the case with a DPS character or a Captain character who cannot afford spare Perks).