It's time to start looking at the problems with the current 2.x resolution scheme as it specifically relates to repository declaration and discovery. I've created the start of a document at [1]. This should be the place to gather feedback and use cases that will help drive towards a more complete benefit and drawback list as well as a list of requirements for a final solution. Please leave comments on the page with things that should be added or changed. Please note, at this point I think it's better to stay away from specific proposals on implementation details. This tends to pollute peoples thoughts on the current problems and requirements, so lets stick to just improving the first 4 sections of the page.
[1] http://docs.codehaus.org/display/MAVEN/Artifact+resolution+and+repository+discovery