I admit that I would have been pleased to see GW walking out there and talking his talk again, and promoting Romney, if only just enough to be just going against Obama.
But I recall that Bush said "I am the reason Obama was elected." That seemed as much an admission of failure as one can make, and a reason to resign from politics. I hear he knowingly awarded pork barrel spending projects to many democratic areas, so they would support his Iraq war. He did not, of course, re-instate the Glass Steigel Act, so the subprime bubble was allowed to grow, and pop. And there was the "Mission Accomplished" and "Bring them on" hypes.
So I would like to see Bush speak again, and that I could see I was wrong about him, but it didn't happen.