After several hours of using Markdown Web Parts in SharePoint I noticed a bunch of issues and raised them in uservoice.com.
I will appreciate the help in solving them or voting up.
Markdown code block: I'd like keep my longer lines of code unwrapped
Markdown blockquotes: I'd like to change alignment to left
Markdown code block: I'd like to put the code in the middle of a numbered list
Markdown table: I'd like to insert a newline in cell
Markdown inline code: I'd like to add email address
Markdown code block: I'd like to choose the programming language for syntax coloring
Markdown editor: I'd like to disable word-wrapping