Rudd is arguably our most important player now given the complete and utter lack of viable back-up options for him.
Ripley just has not worked and doesn't seem up-to it. He didn't get close to permanently dislodging Rudd as No 1, even when Rudd was having a pretty dodgy patch of form.
Crowe is ..... well he is just Crowe. Let him make the brews or something, just do not put him in goal for heavens sake.
Hudson doesn't really seem to have kicked on in recent seasons - could be an argument he could / should have staked a claim to at least be a No 2 by now?
Given the above, I honestly don't see how sticking Corcoran in if something happen to Rudd would be any worse than any other options we have. I believe he is rated highly in the youth setup and can he really do any worse than Ripley or Crowe?