There was a talk (or podcast?) that discussed how cluttered with vestigial options Firefox and other browsers are. One of the examples was JS - if you turn it off entirely it makes the entire web seemingly broken. As long as the option is there for power users, this is the kind of thing that removing will probably cause less headaches for people in the long term.
You're probably thinking of "Checkboxes That Kill": http://limi.net/checkboxes-that-kill/ - and I believe it's what inspired Firefox to remove the option.
