Well, I am a big Lester guy, but benching Eddie has the potential to blow up the chemistry on this team. Eddie is a valuable player and if you bench him you make it way more likely that he will never find his shooting groove. Also, he is one of those players that commands defensive attention. They don't know that he's slumping. He spreads the defense.
Eddie is a horrible matchup against the Hawks. They let Crawford run the backup point and he just has too much speed/height for Eddie to handle. Against most other teams Eddie is fine out there.
I see what you're saying about the "no big 3's" thing, but I just disagree. Eddie hits the shots in the second quarter that allow the game to turn into a blowout in the 3rd. They might not seem so big at the time, but he puts the team up by 10 or so and it demoralizes the other team. He's saving the legs of the superstars.