It would be very helpful if Regular Expressions were supported in Filters/Advanced Filters. The value of the filter function is severely reduced without RegEx support.
To continue on the same train of thought, it would be great if it were possible to save filters once they've been updated on bookmarked reports. I find myself re-bookmarking reports after adding an extra filter parameter or two. If I miss re-bookmarking, then I need to re-add the new filter parameters next time I view the report.