You're not going to get good all-around players for the league minimum and, if you focus your acquisitive efforts on guys in their thirties, you're not looking for potential. The Hawks aren't looking to discover* Gary Neal or Reggie Williams or Anthony Morrow. Instead, they're looking at what guys once were, and hoping that, for another eight or nine hundred minutes, what they are is a reasonable, if faded, facsimile of what they once were.
Vladimir Radmanovic can make threes. The Hawks were 17th in the league in three-pointers made an 18th in the league in three-point field goal percentage. As long as others create shots for him, he should knock them down. He won't turn the ball over. Signing him doesn't signal a move toward a defensive-oriented philosophy, but he's a decent defensive rebounder for a stretch-four and anything that improves the Hawks' spacing will be an improvement over last season.
*Brad Wanamaker, Donald Sloan, please feel free to prove me wrong.