In view of the nearly unbearable slowdowns I experience while composing answers (both in Safari 5 and Firefox 5 on OS X 10.6.7) since June 21/22 I would most welcome a possibility to reverse this state, at least locally on my machine.
The easiest possibility (from the user perspective) would probably be to introduce a user option where one could choose between the options of:
- instant rendering,
- a rendering delay of $5$ seconds (as it was some weeks ago),
- turn automatic MathJax rendering off entirely
while composing questions and answers. If the last option should happen to be implemented, a button "one shot preview" as on MathOverflow would be very nice.