Some of the clipping paths/layer edges on the first one are pretty rough toward the top. But a neat idea. It’s really more a collage than a “hyperphoto”. David Hockney – more known for his paintings than his photography – has done something similar, but with an emphasis on the image being composed of multiple photographs, not attempting to create the illusion of one continuous photo: http://www.hockneypictures.com
If you don't subscribe to the logic and end-user benefits of progressive enhancement, there are probably many things about HTML+CSS+JavaScript that you don't like.
However, what are the arguments for what you are asking for besides easier short-term development practices? And, as said above, there's nothing stopping you from building your webpages that way (especially a “widget” that is self-contained). It works that way as well. How does this make HTML+CSS+JavaScript broken? If anything it is very resilient to different coding practices.
As far as continuous text goes, you're right. These features probably will get used in horrible ways. But even without these features available there are already many well-designed column-based layout examples out there.
Not to mention, "constraints of the medium" could take on a whole new meaning as the wide array of display sizes continues to increase. It will be more and more necessary for web designers to create designs that easily adapt to various displays. They call this "responsive web design" and if you are practicing it right now you are an exception. Soon it will be a necessity and these new CSS capabilities look to be well suited to this purpose.
I guess I think the JavaScript console isn't something a lot of HTML + CSS designer/developers like me know much about. My vision of this tool is to make it for people who know how to drop a few files on their web server, link to them, adjust a property or two and have it working.
I don't know much about the JavaScript console, but since JavaScript can generate both HTML + CSS, there's no reason this idea couldn't be used in that context.
I responded with some changes to your github gist. Thanks! I will now have to try to take this idea to the next level via JavaScript, making it easier for developers to use it and manipulate the settings.