I recently tried out Ulysses. I decided it only had two features I really liked, and a number of things I didn’t, so I’m sticking with Scrivener (which I do really like; I just like to shop around every now and then to see what else is there).
One of the features that Ulysses had that I really liked was that it changed the color of formatted text. To explain: if you made text italic, it would show as both italic and blue. I found this really helpful to see where the italics were happening at a glance, as it can be hard to find if you’re just scanning a document. It was also a great way to see if I was overusing italics and cut back if I needed to.
I could see this as being a useful optional feature for myself and other people.
You could try using underscores instead of italics for emphasis. Scrivener is designed to be used that way, and has an option for converting underlines to pure italics when you compile, in the Transformations compile pane: Convert underlines to italics, in the bottom half.
Ulysses is a different type of text editor that uses plain-text formatting. So the editor is more like an coding editor that will automatically highlight syntax such as HTML, Python or more close to this case, like a raw Markdown file. This type of operation isn’t terribly compatible with an environment where you can do all of that styling yourself with word processor type tools.
One thing you could try is a Formatting Preset that applies italics as well as a text colour, and then in that same Transformations pane, strip out all colour. You could even bind that preset to Cmd-I (though that wouldn’t have precisely the same effect, you couldn’t toggle it off, basically, so I’m not sure how useful that actually would be in practice).
Those suggestions aren’t quite what I’m looking for, but I appreciate it–especially as I didn’t know that you could use underscores instead of italics (I’m used to Markdown with asterisks, but MMD export won’t do PDFs, so I never use it). That will make using Scrivener with Hemingway.app much, much better. Now I’ll just have to see if there’s an easy way to bulk convert italics to underscores or search only for formatted text.
A simple route to PDF via Markdown is the .fodt format. Once compiled, open that in LibreOffice and export from PDF there. There is in fact a “MultiMarkdown->PDF” option in the compiler, however you’ll only see it if you have LaTeX installed. One could probably make use of that for basic proofing style outputs without too much hassle and having to learn LaTeX. You’d only need to get into that if you wanted to change what the output looks like.
So maybe that solves the italics problem right there, but if not, the best way I can think of for getting italics converted to underscores would be to run the text through the compiler (maybe just in a blank project to keep things clean), with Original set for “Format As”, and setting the option in the Transformations pane to convert italics to underlines. Or pretty much any word processor that can search for formatting and do something with it.