I have a lot of friends that love to play in first person perspective (including myself) but I don't use it in dungeons and PVP because zoomed out view give a huge advantage. If you're in FPP and fight a TPP player, you simply have no chance.
I'm not sure how's the situation on PC right now (I didn't play PC version for a year) but on consoles, for some reason all players go to 1 campaign even if it means waiting in a 200 long queue to get in, while other campaigns stay empty. Why not make use of those empty campaigns and convert one of them into FPP only campaign? You would not be able to zoom out the camera. The immersion of huge battles, seen straight through the eyes of your toon would be glorious. Sneaking behind the enemy, flanking and other backflips would finally make sense. You would need to stay more focused and use the environment in a clever way (and I don't mean running around a rock and ganking people..) I know some of you will hate the idea "because if you play in FPP you're a noob!" but it wouldn't hurt anyone. Options are always nice! I'm sure a strictly FPP campaign would appeal to a lot of people, especially the ones that play ESO because of the single player instalments of Elder Scrolls games. Elder scrolls was always about FPP. Stay true to the tradition and give it some more love!