I use compass to watch the folder where my SCSS files are stored and compile automatically on save. That way I can use mapping to find the relevant SCSS, edit it in the browser, and save it to view the changes. It isn't as convenient as seeing the changes before save, but it's pretty close.
Re:Firefox Developer Edition
by sebasmagri on Monday November 10, 2014 @04:59PM
(#8586810)
There is even a Hacks article about that https://hacks.mozilla.org/2014/02/live-editing-sass-and-less...
It would require a SASS interpreter built into the browser, not sure if that's practical or realistic. But it would help a lot for when you need to make edits locally and see the results on a remote server.