This will be a //new// editor, not a modification to the existing wikitext editor, because we want to avoid suddenly disrupting editors and breaking all existing gadgets.
[x] Same toolbar as VE
[ ] Parity + with WikiEditor
[x] Basic toolbar – B/I; sig; link; image
[x] Advanced toolbar – headings; bullet list, numbered list; ~~//nowiki//~~; ~~//br//~~; big; small; sup; sub; gallery; redirect; table
[x] Special characters
[ ] In-editor help
[x] Find and replace
[ ] Nice switching back and forth
[x] A properly integrated experience between the editors
[ ] Section editing
[ ] Desktop, tablet and mobile-suitable (dynamic/responsive)
[ ] Syntax highlighting
[ ] Code folding
A rough //mockup// is [[http://nirzar.github.io/prototypes/ve/switch/wikitext/wikitext.html|here]]. To see the wikitext editor, click the brackets icon in the top-right corner.
A rough **demo video** as of mid-May 2016 is [[ https://www.youtube.com/watch?v=jgd2ZHOZGBE ]].
You can see it in action at https://visualeditor-test.wmflabs.org/wiki/Wiki_markup?veaction=edit