Vimium - navigation inside input fields

Vimium's behavior is in line with Vim's behavior: you have to use the arrows to move around while in insert mode. Note that Vimium's focus is on navigation and interaction with the browser, not on text editing.

If you feel the authors/maintainers should implement that kind of feature, feel free to explain them why in a formal feature request.

In the mean time, you could try:

• TextAid to edit text directly in GVim/MacVim,
• Wasavi to turn textfields into vi clones (I didn't know about it before, interesting),
• Vrome as an alternative to Vimium, note that it uses Emacs keys.