Thanks for these questions. See below my responses.
1. We are evaluating markdown but don't see an advantage over our current rich text editor. Are you seeing anything specific that is missing where markdown editor could add value?
2. We are going to soon add support for exporting attachments to file system.
3. Are you looking to increase the font size in the Editor screen or throughout the app? In the editor we have a zoom feature under more (...) menu. You can try using that as a temporary workaround until we add system wide font size change.
4. Can you clarify what you mean by "expanding gray area"? Did you mean you want to have that type of formatting in the Editor?
1. The things I'm missing the most are headers, to add more structure, and checklists. Headers I can maybe live without, but lack of checklists is a big problem for me. There are other minor things, but mostly it comes down to habit since I'm constantly using markdown in my writing and note-taking apps.
2. Glad to hear that.
3. Yes, font size is what I was interested in. But then I noticed that templates seem to use different font (with no lower case letters) which was also bigger then standard font used for body. It is a bit confusing not being able to do anything with fonts, yet having other fonts/sizes already used in templates.
4. Similar to my previous point, it's not that I explicitly need it, more like "Okay, I see this nice formatting used in templates, how to I create the same thing manually? Oh, I can't...". I could use quote formatting in place of it and it would look almost identical, but why can't I use the same thing templates use? Feels weird.
The font and grey area I was talking about: