The unfortunate truth is CMS's are ten a penny these days and to knock the big boys off is near impossible
Yes it looks good, yes it looks promising but yes there are 100's of CMS's already built out there that do this exact job.
Good luck with the endeavour but I think you are about 5 years too late
My point really was that people will always want more, more power over what they can do and it's quite easy to lose scope and start putting more power into the solution.
We developed our own CMS at our company, it's not for outside world usage but for internal so it's not that I am adverse to the development of them. If I was a company though, I see no issue in downloading Wordpress and buying a template. You get the added knowledge that you can get 1000's of widgets and you can virtually drop them anywhere onto the design of your choice.
I sincerely do wish the develops all the best in such a competitive market and hope that the niche they offer hits off with designers.
I'll i'm saying is, don't lose scope.
I do love a good keyboard warrior