Description of first level of combat dog perk says that it allows better targeting of enemies in WATS. But does this perk works outside of WATS too? So far I did not notice difference. Dogmeat tend to "hold" or drag to the ground some enemies even without this perk.

Can somebody clarify?

He still grab and kills even without the perk, the perk just buffs the action with some passive benefits.

And I would assume it does not work outside of vats, luckily the remaining ranks do work whether ya a vats user or not.

You mean the next ranks which can cripple limbs and so on?

Indeed that's my impression so far. I was hoping someone can confirm that.

Yep the crippling and bleed effect.