Humm.... I see GhostDoc no longer appears in Add-in Manager either. To me this is not good. Usually my development environment is stable, but occasionally things go wrong and it is useful to be able to quickly turn off Add-ins while troubleshooting.
Another major reason why I like being able to quickly disable Add-ins is that I mentor beginning programmers in our company. As a rule they do not have all the Add-ins that I have, and some of my Add-ins (like ReSharper) change VS's menus quite a bit. It is beneficial for me to be able to have the same VS environment that my mentees do and Add-in Manager is a quick and easy way to do this.
Please seriously consider supporting the Add-in Manager paradigm with all your VS tools. I would really appreciate it! 
Thanks.
-- Mark