As I said before, there may be better options available. Guys like Janero Pargo, Brent Barry, Tyronn Lue, Anthony Carter, Chris Duhon, and Carlos Arroyo all might be better fits.
Still, as I said earlier, we're in a slightly better spot this year than last in terms of point guard because of the evolution of Rajon Rondo over the past year. Given that it's reasonable to expect him to be even better next year, the need for a solid backup is less. So if we took Cassell or House back, it probably wouldn't be the end of the world.
Still, as this year proved with our close game 7 victory against Cleveland, even the little things matter. So having the best PG play possible will be important. Plus, as my father noted to me yesterday, with Rondo's slight build, it wouldn't hurt to have a solid backup in case he does go down with an injury.