If there is no quick and easy way to do dungeons you will lose the casual players, those that have limited time to spend in the game and dont want to idle spamming for the most of the playtime.
Also the argument about lfg bringing out the worst in people is wrong, thinking you are better than others bring the worst out already, happens in groups already, some "elite"player whining in group cause some "ebay" player did not know the dungeon. No wonder, was probably his first dungeon in the game. A jerk is a jerk anyway you look at it.