Gay is a decent defender when he's not forced to play center against bigger guys. He'd be fine in a 5 out situation. Love is a better defender than Bogey. Mitchell and Conley are both decent defenders and give far more on the offensive end. The Jazz's defense will be just fine with Gay and Whiteside back as long as Bogey and Clarkson don't play. They are the Jazz's 2 biggest problems right now IMO.
The Jazz could also use an enforcer type guy to bring some toughness.