There are four main outcomes which means four trophies so you can't get it all through one play through. It is a RPG, make more then one character. If you don't like the idea of Role Playing why are you playing an RPG?! You can't finish the game with NCR and then turn around and side with Legion. Does not work that way. Game has multiple endings and multiple options to play.
i think he means he is in favor of the ending being completely meaningless so he can have his meaningless post-end grinding.