While I like the AGPL, for projects where it's appropriate (I think it fills a need to ensure that users of the software have the four freedoms, even if they only (mainly) use a service, not a local program) -- I also generally think libraries are better served by LGPL.

It's a rather complex issue -- not just how do delineate "libraries" as opposed to "derived works" -- but also how much is needed in the "main product" for it to be useful. Architecturally it might make sense to have the "program" or "service" be a thin wrapper around several libraries -- but if only the program is AGPL, and the libraries are LGPL -- how do we make sure the end user is free to maintain the software if needed?

The main thing with the GNU line of reasoning, is user rights. If viewed from the perspective as "just" a developer, many of the licenses look restrictive -- because it limits the developers power over end users.

I think we all end up with more freedom as a result of that -- not everyone agrees.

As for mixing -- I'm not sure how the "open source" exceptions in the license are supposed to affect that -- my cursory reading seemed to imply that the idea was to allow mixing with code under other licenses. But I must admit that's not a subject I've considered much.