Feature Request
It would be useful to have a GitLab Flavored Markdown card in the editor (or any other Markdown flavor that is smart enough to solve some issues and simple enough to not bloat ghost’s code).
It would solve some known issues that remain existing in the name of backwards compatibility.
What it would solve
Actually I was about to open an issue in the github repo about how “wrong” ghost do that heading-to-IDs translation, then I found other issues about this very same problem, being closed as “expected behavior kept to not break backwards compatibility”.
I’ve started with ghost a couple of weeks ago and felt in love for it. Actually what brought me to ghost was the screenshots of the old “native markdown” editor. When I realized it changed, it kinda disappointed me, but then I discovered the Markdown card thing.
My thought: “Uhm… Using a markdown card for my entire post looks like a workaround, but OK, the other ghost features makes it worth it”.
You guys may be well aware that Markdown users love to write using pure Markdown. They also love to edit using Markdown even after the post is published. I think that it’s one of the favorite features for “tech bloggers” (and even the non-tech ones).
Then I started bloggin with ghost. As I’m blogging in the portuguese language, after a couple of posts I faced the problem described in #9740 (id names missing special chars and spaces).
Checking the comment on that issue made me realized that I can break my post into several Markdown cards and create the headings outside the cards.
Ouch! 
It’s going to be a really ugly workaround that will surely be a clutter to anyone’s writing flow. But, ok… let’s tolerate another workaround and keep taking advantage of ghost’s cool features.
Then I created the heading ## Isso é só um teste, and it generated the ID isso-s-um-teste (while I expected to get isso-e-so-um-teste).
I’m really enjoying ghost this bug behavior (kept in the name of backwards compatibility) is a big disadvantage for me, and I think it’s the same for many bloggers writing in non-english languages