Cabal and installing packages.

Just been thinking about making Haskall packages easy to use and install, and someone suggested I looked at Cabal. It seems to me at first glance that something important is missing... If we imagine some easy to use wrapper program for the user, which would allow them to specify a library by name, and which would download a list of mirrors from haskell.org, then fetch the package, configure, compile and install it. It seems the library author should specify the dependancies of their library so that the prequisit packages can be fetched first. My question is does Cabal require the package author to specify dependancies, and if not, perhaps it should. Regards, Keean.