I just had a problem with the XMLTV EPG where the guide couldn't be pulled down. I submitted a post, timeouts were briefly discussed, etc.
Then I remembered seeing the option to delete and rebuild the guide. So I went in and did that. Of course, that solved the problem. But it also made me think about doing it on a regular basis.
Nightly is way too much, but what about adding the ability to schedule a guide delete and rebuild weekly, bi-weekly, and/or monthly? Having it happen every Sunday at 2am would be nice.