Given that Google Closure optimizes out unused code, I'm going to guess that the more that the Google Closure library is used, the more of it will be added to the minified source.

As a point of reference, their sample twitterbuzz app which uses the Google Closure library is 100k minified.

That being said, this is alpha software so it's hard to criticizes it's lack of output optimization at this point.

I guess I don't see how this is any different from the kind of expected bloat that say jQuery UI adds to a project.