Firefox can either choose to keep up with new features or lose 90% of its share to Chrome. I'm actually happy they going forward because part of HTML5's appeal is that it is multi-vendor and is not solely controlled by a corporation like Google or Apple. Yes, it is "bloat", as in, lots of new features that you personally might not be using today. But someday you, or your friend will come across a site that uses one of these new features and if the site says "Sorry, you are using a backwards browser, please try Chrome instead", we both know what will happen. (You of course will scoff and close the site, but 10 other people will switch for every lean browser snob out there.)
Point is, browsers are evolving. Deal with it.