I think we also need a few more features:
- Minifying JS, CSS and the HTML that is being sent down the wire.
- Caching the op-code of the PHP that will be generated (apart from Memcached).
- Upload the JS, CSS and Images that are used in the theme and/or plugin to a CDN and sync automatically.
- Option to use one of the public CDN netwoks like Google for common resources like jQuery.
- Offer a common CDN for all the WordPress admin scripts and images (which should be the exact same on multiple installations of WordPress) so that I can have that work just a little faster.
- Managed DNS – To ensure that they can restore a backup of your site on another location automatically in case they have issues with the current hardware. With this they can automatically switch your domains over to the new settings.