One day, after all the issues with the 5DII are resolved, I plan to get one. I will keep the 40D. That way I have both and crop and a FF camera. It's like doubling the lenses in my bag with one purchase.
All the issues will never be resolved. At some point you just learn how to deal with them or avoid them all together. Take the 40D and 85L for example... How long has that been reported as a widespread issue and it still appears there isn't a fix for it?