Now that we have the rep report pages, what problems would arise if running the report also performed the recalculation on the live database (with a suitable warning/are you sure? message of course)?
Would there be an extra burden on the servers? I can't see it would be any more than at present with everyone trying the new feature out.
If this were the case and well publicised then there'd be less need for there to be a scheduled job running to do this for you.
I suppose what I'm trying to suggest here is that if rep were seen as a more fluid thing that did go down on a regular basis due to deleted posts then if there was another major change it would be seen as less of an issue that it has been (for some people at least) for the last couple of days.