Excellent, plain and simple.
This shoould be native (core) joomla component/module.

There's a little bug when you edit a couple of times some module, for example if you want to change blog to list layout or vice versa, the link adds every time that option..

http://www.site.com/index.php?option=com_content&view=category&id=10:mytitle&layout=blog&Itemid=12&layout=blog

but the links are still OK, which is I guess more important than the small bug in URL.

This is what I've been searching for...
Great idea of the author!

But the keywords system is a little bit complicated for less experienced users (site editors). They got confused easily to follow the structure for every article, sometimes they miss one letter or write it with a space, so the 'check button' system with predefined keywords would be a big plus to this extension.

Everything else, even when you need to list only articles from a 'current category' is cool...

Keep up the good work!