We would need the spell checker to be reactivated and modified so that articles can be checked on their own (rather than giving a huge list of all pages with particular errors in them). I don't fancy copying entire articles into MS Word to check for errors (and people checking articles for correct spelling would be likely to miss many errors). I know the spell checker was a huge resource drain on Wikipedia, but if it is restricted to those permitted to validate articles, it shouldn't be so bad.
~Mark Ryan