It looks like the new Planet that you guys just shipped doesn't have all the legacy mzscheme packages that used to seem to be the majority of packages. I don't know if that was intentional, but if not, I think that it's a nice tangential benefit.
I just remember every time I'd search for something on Planet, most of the results I'd get back were for old scheme libraries.
I know it's annoying as a developer to hear a vague criticism like "there's less useful libraries" without being able to provide a list of concrete items; but I'm going to annoy you by not being able to come up with anything specific right now. Sorry ;)
I will say though, I think Marketplace looks really neat, and I'm looking forward to testing it out for some things internally.