This isn't an argument for or against First Person or Third Person graphics--This is something a little different. A seemingly minor, but to me, significant change, in adventure games, went from the protagonist being referred to as "You" to the protagonist being referred to by his/her name.
For example, in KQ's 1-4, the player is referred to as "you" by the narrator. Not Graham, Alex or Rosella. The narrator also often directs comments straight at you in the early games, besides giving the standard descriptions--for example, in KQ4, if you type in for Rosella to undress, the narrator tells you, "Not in front of the players." But in KQ5, it changes. The narrator becomes only a vehicle to describe the environment or an action; the narrator is no longer a "character" in some ways; also, the protagonist is no longer called "you", it's Graham. Subsequent games follow this--in KQ6, the narrator refers to the protagonist as "Alexander", etc.
I think this small change in the interaction between the game and the player is significant, in that it in a way removes you somewhat from the game. The player character is no longer you, it's a character you play--it's a subtle, but significant difference.