Hi,
I don't like libraries getting bigger, I like them getting smaller.
When they're smaller they're easier to understand and easier to upgrade.
So I would also advice proposing your package for the HP (Haskell Platform).
I'm even for splitting containers into sub-packages: maps, sets, sequence, graph and tree. Those sub-packages would then need to be added to the HP.
Then we could turn containers into a meta-package that depends on these sub-packages (similar to how the HP works[1]).
Finally we could deprecate containers and after some time remove it.
(I'm also for splitting base even more... but one thing at a time)
personally I am against splitting containers. It is a collection of several basic data structures with similar design decisions (reasonably efficient, can be used persistently, decent API). I think these structures should stay together, to have a library of data structures for common usage. I am for adding the priority queues to the containers. Cheers, Milan Straka