The Jazz need to ask themselves how much they really value Royce O'Neale. He gets praised because he doesn't take shots away from other guys, and he's a tough defender against certain forward matchups. But he isn't irreplaceable by any means. Royce + Joe + FRP might get some traction, since either player could then be flipped for another pick.
If the Jazz upgraded Royce with Harrison Barnes, I think that would put them in the Finals. They'd be adding rebounds and offense, while maintaining or improving their defense. Rudy Gay is also capable of picking up a few extra minutes if need be and Trent Forrest can continue to play some minutes against bigger guards. Paschall is also fine for a 9th or 10th guy.
I think Barnes is the obvious guy for the Jazz to go after. He's more skilled offensively than Jerami Grant, he'd be able to move the ball in Quin's system, and he's also a better rebounder than Grant. A lineup with Conley/Mitchell/Bogey/Barnes/Gobert and Clarkson/Gay/Whiteside off the bench is really solid and borderline unguardable.
http://www.espn.com/nba/tradeMachine?tradeId=y3ubbhff