This would absolutely be better solved by an entirely new application, written from the ground up.
And the whole-page-is-images thing really bothered me too. Some nice designs and interesting ideas for sure, and knowing CSS isn't a prerequisite for being a designer, but damn, I have some doubts about the understanding of the technologies here.
Which is probably exactly where the concept of "forking Wordpress" came from—a misunderstanding of exactly what that would entail.
Modern rewrite is what's needed, definitely. But don't call it anything related to Wordpress. Don't need to.
I've been committing code to the core WordPress codebase for 3 years, so while I'm not a PHP developer - I have some idea.
Perhaps one thing overlooked in the argument for fork vs new build is that there aren't a huge number of developers with the skills to make this happen who would do it entirely on an Open Source contribution basis as opposed to, say, a startup basis. Appealing to existing WordPress developers, businesses and users, as well as cutting down time to ship first working concept, are (in my mind) some important arguments in favour of a fork.
I'm relatively new to the WP scene, and already its totally clear that WordPress is tolerated because it has a vibrant ecosystem. Getting to keep that is way bigger factor in uptake over the next five years than anything a rewrite could deliver.
I think you could gain momentum surprisingly fast with a new project if it offered a quality alternative. (I say this as the author of a CMS in another content-type space which has done that fairly well)
First, let me say this: I love what you've done with the Ghost design. I think it's clean and useful. More on this below...
I am one of the early contributors to WordPress (you'll see my name on wp.org's About page near the bottom), and one of the founders of the Habari Project. We started the Habari Project for many explicit reasons, but in part because the curators of the project (Automattic) were not behaving in a way that we felt was beneficial to the community they had begat. So let me tell you a little about our project:
Not only is the Habari Project an entirely Open Source platform, but it recognizes participants in the project appropriately based on their contributions, something that I did not observe during my tenure working on WordPress.
Habari employs the Apache Software License, which is more permissive than WordPress' GPL. Want to develop a plugin or theme? Is the code tainted by the GPL? In WordPress, I don't really know for sure what parts can be redistributed, if any. In Habari, you can sell your themes and plugins for profit if you want to, or contribute them back to the community -- most themes and plugins so far have been.
The passion of the Habari community for producing good, documented code has (in my mind) been one of the driving forces behind WordPress' "recent" adoption of similar policies. The quality and friendly tone of assistance I get from people who know about Habari has been consistently orders of magnitude better than anything I've seen come out of WordPress, which is a characteristic that everyone working on Habari strives to maintain in the project. One of our guiding principles has been to be a project that is useful for web development education; We've seen a lot of people join our project and learn how to code well, both in the method they use and in the collaborative environment our development often lives in.
We've accepted a policy of keeping up with as current a deployment of technology and standards as our core users can stand. We recently adopted a PHP 5.3 minimum version, and I'm pushing hard to take that to 5.4. Habari simply does not run on PHP 4, and never will because it's no longer secure. We code for HTML(5). We're using CSS3. Our roadmap (admittedly difficult to find online) includes PSR-0 and namespace adoption to more easily integrate with vendor libraries. The use of current technology and techniques is really good for developers, and a refreshing change from projects that insist on supporting every old (insecure) server architecture out there.
And I'm currently making a living (yes, paying the mortgage) deploying Habari as a CMS for clients. It is viable. It is open source.
I know first hand how long it takes to build a working product with a small community. We are admittedly behind in our implementations of some features that WordPress was able to steam ahead with due to their larger community. There are also non-dev areas like marketing where we could use some work. We've been trying (albeit weakly) to lure those kind of contributors to the project.
We had a talented designer help us with our current admin design, and one of the things people comment on most about it is how it's not as cluttered with st as WP's. I like the design you've used in Ghost because it's similar to ours, yet modernizes, and I think our community would like it, too. We've been talking heatedly about a new admin design for our next release...
Habari may not be the thing for you, but I do encourage you to take a look, visit our IRC channel on freenode, and take from it what you can. If you still want to try to bend a WordPress fork, I'm at least interested in the story of your effort and struggle. And if you want to chat about why we started over (though I think it's obvious, maybe it's not to everyone else) instead of forking, or why a new project with a handful of addons (compared to a competitor) can still be a contender, I'm happy to chat. Here we are: http://habariproject.org/
I looked at the code, installed a test site and read the Wiki. Is this project on a down low at the moment with only 19 commits and low activity since late last year ?
Also, when you mention that you manage to pay the bills with development of habari powered sites, do you draw from a community need for habari developers or are these clients that you persuade to use habari ? I'm curious about the overall community and where it's going.
In my work, clients mostly need a site built to perform a specific function, and if Habari fits that task, I use it. There isn't an explicit demand for Habari developers, but there is a high demand for sites that Habari is suited to produce, which overlaps a bit with WordPress' capabilities.
As others mentioned, the main habari/habari repo commit count is low because the main development doesn't happen there, but in a submodule'd repo, habari/system. The purpose of this is to allow you to easily fork the main repo to add your own plugins and themes to it, while the submodule continues to pull from the system repo. It's very beneficial from a maintenance standpoint.
I'm not sure how to explain the community. My involvement has been nothing but beneficial for me, and it has been a similar experience for the people I know the community has touched. Development has been reasonably continuous, as you can see here: http://www.ohloh.net/p/habari
http://octopress.org/ is essentially something written from the ground up that addresses many of the concerns in ghost, but that doesn't mean its the solution.
Because WordPress is built on PHP it has a wider array of deployment options, including many low-cost options, while maintaing a relatively easy to use sheen.
I think it makes sense to evolve WordPress to merge the benefits of something like octopress with WP.
And the whole-page-is-images thing really bothered me too. Some nice designs and interesting ideas for sure, and knowing CSS isn't a prerequisite for being a designer, but damn, I have some doubts about the understanding of the technologies here.
Which is probably exactly where the concept of "forking Wordpress" came from—a misunderstanding of exactly what that would entail.
Modern rewrite is what's needed, definitely. But don't call it anything related to Wordpress. Don't need to.