I don't think that there is a good place to do that, unfortunately.
You could file a bug, but it'll be pretty much lost among the thousands upon thousands of other ones that already exist and haven't been dealt with.
You could comment here or in some other discussion forum, but those in the Firefox community will probably just vote you down, and continue to pretend that there isn't a problem.
You could write an article, but again, that probably won't help much, unfortunately.
The best thing to do may be to find an alternative browser, or use older browsers that aren't broken in this manner.
I just don't think that those working on Firefox these days truly care to listen to what the remaining Firefox users have to say. Time and time again lots of users have loudly expressed extreme displeasure with monumental mistakes like Australis and the removal of useful functionality, only to be totally ignored by the Firefox developers. I don't see why this situation should be any different.
