I don't even think Richards has been playing well on the Fourth line.
That's your guy's eyes playing tricks on you.
Since this series has started the Kings have had one good Center(Kopitar).
2-4 have sucked pretty much since game one.
Carter/Stoll/Richards have been getting outplayed since Game one of this series.
At this point I would move Richards to wing, keep him away from the Center ice position.
Maybe even move Carter back to wing, he is hurt (obviously) and not shooting or defending.
Kings have been weak down the middle these last four games, it finally showed up on the scoreboard.
He hasn't played well anywhere, which is why you leave him on the 4th line, matched up against the sorriest competition possible. Then at least he doesn't totally screw you over. Or you think like Sutter and put him out against the other teams top line and watch it cost you the game.
Look, I like Richards and I like Sutter, but there is absolutely no reason that Richards should be anywhere but the 4th line. None. Maybe the Kings don't win with him there either, but at least it gives them the best chance, and that is exactly what the coach's decisions are supposed to do, give you the best chance. Not cost you games because you have a candy assed obsession with Hallmark moments about the good ol' days when Richards didn't suck.