I just don't see the point in bringing back Thornton. He really doesn't add anything the team needs. Thomas is our bench gunner, and a [dang] good one at that. No need for an inferior version of what we already have.
That aside, Smart, Bradley, and Thomas should be getting the majority of the guard minutes, now and going forward. Beyond that, I'd like to see James Young get more of a chance next season to work his way into a larger role in the rotation. His shooting and size would be a nice change of pace from the other three guards. To round out the guard rotation I think the team would be best served by bringing in a low-usage vet who has a bit more size than Thornton and is a more steady hand (i.e. someone who plays a more fundamentally sound game).