Whether Rondo or Westbrook is a better player has been discussed ad nauseum around here so I won't rehash that argument.
Another point worth looking at is the contract situation. Westbrook is going to be a free agent after this season. It's then somewhat likely that he'll sign somewhere else or ask for considerably more money than we are paying Rondo.
Even for those who think Westbrook is a better player than Rondo for the future, I don't see how this makes any sense unless we really want to start over and are more than happy to take the chance that Westbrook walks after this season.
Having a top five, young point guard locked up for the next four years at a very sweet $11 million per is one of the strengths of our team moving into the future.
I'd like to keep our team together for another run at it, but for those desperate to make big moves, trading away one of the aging, expiring contracts seems like a vastly more sensible approach to rebuilding than looking to "upgrade" at the pg spot.