I see huge bust potential with both Irving and Williams. While i don't think Irving will be horrible, i don't see him being the star point guard that people think he will be. He is a pure point, but it looks like he may be close to his ceiling already, but i've been wrong about point guards in the past, and i did suggest that the Bulls pick Beasley over Rose so hey this could be a repeat of the past.
In the end i would pair Williams and Kanter if i were the Cavs, Ramon Sessions has already proven to be a more than serviceable starting point guard.