A catcher provides two services to the pitcher; calling the pitch, which the pitcher can shake off if he's not happy with it and providing a target.
It's not really that complicated.
Like I posted before; even V-tek couldn't make Kluber effective. Kluber can only be effective when he has near perfect control, which is hard to accomplish consistently.
Tough decision for Cora when Whitlock returns. He can't put Kluber in the BP, unless it's strictly for clean-up duty. I'm guessing if Kluber gets Klubbed in his next start, he might be either put on the IL or DFA'd.