That is a great a suggestion Brunt, that Archer lose an eye. It's a great suggestion for ANY of Star Trek, permanently damage a main character. Even better in ENT since the medical field is less magic. Archer loses and eye, is scarred and patched and very very cranky.
I'm scratching my head now, I recently saw some series where one of the main or supporting characters who had been quite okay looking ends up disfigured for the rest of the show.