This probably puts the nail in the coffin for Gitaxian Probe being unrestricted (and rightfully so). It's just hard to argue that the rationale for banning in Legacy (information at too low a cost, a free spell) doesn't apply to Vintage.
Paradoxical Outcome is likely a card with a fixed lifespan. It's not a balance issue from our metagame data. It's not a diversity issue, either. However, it does have a pretty high "brokenness" factor, leading to a lot of blowout turn 1 to turn 2 wins. I think the more Vintage players run up against it and the more these wins accumulate, eventually public sentiment will turn against it. I know many players don't believe that should be factored into the equation, but it's pretty clear Wizards disagrees.