The type of plugin you're describing would likely allow for the uploading of any C2 exported project and would then make it easy to include the project in a WP page.
Ugotsta
Yes, that's exactly what I mean, and what qualifies as a WP plugin in my book.
It seems to me that all the handwork required by your form/tool could/should be automated by a generalised WP plugin for C2 HTML5 exports. For example ...
I've just updated the tool so it now asks for height and width and includes that in the output canvas. I couldn't easily regexp search the original c2runtime.js for height/width, especially since dimensions are per-layout, so I've just added it as a setting in the tool's page.
... you don't need to regexp search the original c2runtime.js for height/width (they're not there anyway), much less ask users to type them in - they can be taken from the C2 generated index.html (after all that's essentially what the c2runtime.js does).