What do you want your experience to be like in 1st Person?
I avoid first person in RPGs when I can. :shrug:
I like it in shooters of course, but its just not the point in an RPG. In past TES games I play as far back in third person as is practical, and only resort to first person when the map design makes it all but impossible not to [tight caves and hallways mostly].
My real answer to the question would be, "non-existent", but FPP is a design intent of the series and should always be improved upon rather than removed. I just hope TPP play is still possible at all ~they crippled it bad on purpose in FO:NV, and the fix for that was the first mod I went looking for.