MS Help Team have just released a new Help Viewer.
It can be run embedded in a browser or run standalone.
It has the full index but still the lo-band TOC experience.
I had to reboot the PC (as well as restart Agent) to make it work. I'm currently having problems with all browsers except Chrome. I hope you have a better experience. For me this is a very ruff first release which I'll uninstall for now and wait until they fix it up. Thankfully when I uninstall (no reboot required), the old experience is fully reinstated.
Here are some screen shots.
In embedded mode a left hand navigation panel (done in Silverlight) appears for http:///127.0.0.1:47873/ type URLs.
The TOC is lo-band style.
Index - Disambiguator items show inline.
As you can see I'm not seeing any branding in the content pane.