It would be nice if the report dialog box would be pre-filled with a suggested name based on active pane's file and directory.
Perhaps something like ".\filename.ext.htm" would be convenient.
On a related note, I've said it before and I'm saying it again: It sure would be nice if Moved-Text sections in the html report would hyperlink back and forth between to two positions for that text. This seems like it should be a fairly simple thing to implement, and would offer significant utility in reviewing a difference report.