CWG is modified with several extra features that the CWG team decided on, mostly in a vacuum as I understand it. So unless I've missed something it wasn't really a truly open community effort. Also, the focus wasn't placed on stability and bugfixing, but rather on enhancements and new features.
There was also word that there's been a CircleMUD 3.5 release that's had a lot of work done on it, which may be more what you're looking for.
And besides, why would we want to undertake a project that you've indicated would take us much more time than the one we already have going? Smaug has taken 10 years to get to this point. Spending 10+ more on a codebase most of us don't even like? Not terribly appealing.