The Tor Browser Bundles will include Torbutton, but we will no longer recommend that people use Torbutton without Tor Browser. Torbutton will be removed from addons.mozilla.org, and the Torbutton download page will clearly state that it is for experts only. If serious unfixed security issues begin to accumulate against the toggle model, we will stop providing Torbutton xpis at all.
User model breakage was one of the failures of Torbutton: Even if users managed to install everything properly, the toggle model was too hard for the average user to understand, especially in the face of accumulating tabs from multiple states crossed with the current Tor-state of the browser.
Another failure of Torbutton was the options panel. Each option that detectably alters browser behavior can be used as a fingerprinting tool. Similarly, all extensions should be disabled in the mode except as an opt-in basis. We should not load system-wide and/or Operating System provided addons or plugins.