I guess it comes down to figuring out what kind of CMS we want to build. Do you want a CMS that is easy for web designers (like WordPress), or do you want a CMS that is easy for end users? My feeling is that there are already SO MANY WordPress clones out there that if we are going to build a "kickass" CMS, it should be easy for end users. I started to design a CMS for just this reason, but I haven't had a lot of time to mess with it recently.
My thought process when I started to design the CMS was to make it dead simple. If you know how to check your email and/or Facebook, then you can build a website. I had a working prototype of a CSS designer that was used to make themes. I had also come up with the idea for blocks (this was before I knew about Concrete5) where you select what type of content you want for the block (Markmin, HTML, RSS feed, tag cloud, nivo slider, other widget, etc). Then when in design mode, you could drag blocks around, resize them, etc. The result of this design was a CMS that allowed users to create entire websites using pre-created components and widgets without knowing anything about HTML or CSS. Adding new widgets, plugins, and components would be simple for developers. And dropping down to regular HTML for a block was always an option incase something complicated needed to be done that the plugin system didn't cover. This is the kind of CMS that I would love to see, and I know for a fact it is in high demand. But, it's difficult to develop which is why no one has really done it before (Concrete5 got close, but you still have to build themes/templates using HTML). So if we are going to build a CMS, we might as well make it "kickass".
