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.
_underscore_ for italics conflicts with most identifiers in most languages.
Markdown was created in an era before the web had easily used components for structural syntax highlighting (tree-sitter) and where reliance on regex-based approaches was more common.
> Maybe using an unnatural placement of )parentheses( could have worked as a non-conflicting indicator of italics.
Using different delimiter for opening and closing is a good idea on its own, too. I think it makes parsing simpler and unambiguous wrt nesting.
I've imagined something like this:
Probably looks a bit more distracting, though.