I think from the very beginning it was clear they are doing only FPP. Or at least from the moment they started to talk about the game in some detail.
And in this case, it is not like they could just add TPP, it seems the game is built around the FPP to the very core. This includes, I suppose, how the cutscenes are working fpr example. If you have "cutscenes" in FPP, especially if you controll the character, I don't see how it could work in TPP. I've read they put a lot of effort in the cutscene system to make it work in FPP.
Generally I prefer TPP games (aside from shooters), but in this case I am glad they made this choice. And Kingdom Come deliverance taught me 100% FPP view could be super immersive. TPP cutscenes/dialogues were really breaking the immersion in that game.
Also, people should really not expect this game to be sci-fy GTA... Personally i would be disappointed if it was, but I think some people could be disappointed the other way around. The marketing will be to blame in that case, but still. It is an RPG - and recent previews confirm that. I've read in several places the marketing does not reflect 100% what the game really is...