I find the readium project to be haphazard. As a developer, looking at the source code it looks like bits of code put together by somewhat disinterested developers. It seems to lack direction as far as the ultimate reusable end product. Since this is a rather serious software engineering project (I.e. reusable rendering engine component for EPUB3) I wonder why this is so. Why is there no upfront design for functionality that has clear requirements specified in the EPUB3 specs?
Why can I not just grab a binary that gives me an interface with a small set of methods that do exactly what it is intended to do?
When I use a rendering engine component for EPUB3, I expect it to ask me for an EPUB3 zip file, open it and return me a set of pages, at the very least. Additionally it should return metadata and resources like video and its position on a page/screen bitmap. I expect it to deal with HTML5, SVG, CSS, MP3, MP4 and any other formatting technology that is required by the spec. I, as a developer, can then by having a high level understanding of the EPUB3 spec, know exactly what to do with the pages.
Finally, and most importantly, why is readium based on WebKit? By my understanding the requirements for an EPUB3 rendering engine is not an extension nor is it a subset of the requirements for an HTML based browser engine. The EPUB reader is not a descendant of the browser, it is somewhat of a cousin. EPUB borrows heavily from the technologies required to render web pages, but an EPUB page is NOT a webpage so isn't it somewhat unpragmatic to have the one reference implementation for EPUB3 based on an engine that arguably is not designed to implement the same set of functionalities? Apart from the bloat and unnecessary functionality, you will also have situations where a developer tries to hack a similar functionality to an EPUB3 functionality causing all sorts of software problems and creating future bugs and headaches.
It is somewhat worrying that the entire publishing industry is waiting on this Readium project as the catalyst for doing good business with ebooks. I think it's a disaster in that sense. A tragedy even since everyone is waiting on this one project that is bound to fail.