If you think the "fun vs skill" way then might as well think about your other static members - not sure if they have fun too if you suck at your job. Might end up having the title of "that guy" and other people trying to find reasons why not to do endgame content with you anymore.

From personal experience I use Warrior for fun (and let's say my skill at job could be better). I use WAR in 4 man dungeons or Syrcus. The thing that I truly feel the most is when my team has DPS that deal no damage - because I know how fast that monster usually die and now that ilvl 100 dps is trying to kill it for twice longer. As it doesn't make me mad in dungeon where it doesn't really matter - things are different in Coil and ex modes.