I have suggestions for you, hope you like them.

First one:
Answering to this post, I find a little confusing the screenshot but I guess that in the practice it should be easier. I think I get the point with the “click the category, now magically click the categories alike”.

Second one:
There should be a view source that doesn’t use external apps. Most of the time (almost always) you want to see the source code of a web page to look for errors or see “how they did that” so opening gedit just for reading 1 or 2 lines is annoying. However I get the point about the integration in the desktop, maybe this should be a extension of epiphany in a “default” extension package.
This makes me go to Firefox always.

Third one:
Have you seen the webdeveloper toolbar of firefox? THAT is a killer feature in firefox. If epiphany gets an extension like that (in fact if epiphany promote the creation of extensions) firefox will be history for me.

I’m mainly worried about the features for web developers, I would recommend that you take some focus on it.

I hope you liked the comments, keep up the GREAT work!