I agree that using *asterisks* just feels wrong for italics, and are much better suited for bold. However, surely the _underscore_ is just perfect to visually indicate underlining?

As for /slashes/, which would visually be perfect for italics, the only reason they conflict between italics and filepaths is the fact that in both cases they are expected to be used at the beginning and end of a word. Maybe using an unnatural placement of )parentheses( could have worked as a non-conflicting indicator of italics.