I feel that the markup editor can be tweaked to make entering content a little easier.
1. If the line is indented by n spaces (usually the case while showing code), then preserve the same amount of indentation when "return" is pressed. This is especially useful while entering wiki text for planning code-related stuff like APIs, etc.
2. If the "tab" key is pressed, insert a tab character or 2/4 spaces in the text editor instead of jumping to the next button.