I think looking at something like Dues Ex is useful for this kind of discussion - that game works incredibly well, feels very immersive, and still has some third person elements when you grab cover, for example, so you can still have that nice “spacial awareness” third person provides.
I also agree that melee based combat, like Dark Souls or Witcher 3, is best in 3rd person. Any time I’m playing with a shooter (or spell caster in Skyrim, for example) I’ll go 1st Person every time. In fact, I suspect first person melee is what ultimately killed Kingdom Come for me.