According to a prerelease notice, there is a forthcoming OS 10.7 update currently in beta that addresses this problem specifically.
I know some of us who are justifiably frustrated with this problem (this is a piece of productivity software, after all!) might be a bit cynical regarding Apple's responsiveness or lack thereof. I suggest that people make ample use of Apple's feedback forms and leave detailed feedback regarding the performance of their products.
The one for Keynote is here: http://www.apple.com/feedback/keynote.html
My only gripe with Apple in this particular situation is that it didn't simply put out a tech sheet and a packaged temporary downgrade to iWork 9.0.5 for any user experiencing difficulties on OS 10.7. It's far better for users when a company acknowledges a problem and provides a solution, even temporary, rather than make it "go away" quietly with the next update. At the very least, this would acknowledge the inconvenience experienced by users who rely on this software for their work. Shareholders and investors might feel differently, unfortunately.