well one thing would be the german layout -> shift + 2 which is on the english layout an @ sign but in the german one a double quote.
this is the one thing. besides that I'm a person who focuses on functionality more than style. so I personally would like a text area with no fancy auto-complete just pure markdown support so I can write what I mean an not what the editor thinks I could mean based on the assumption of the implementing party.
I'm a bash person ;D ....
that's it, I just have way to many things to do at the moment to be more active than I am now. And if I see good answers that nails it I don't write my own. I am even inclined to delete my own answers if I think they distract from a good other one.