Too busy to have thoughts on this at the moment but here's the link:
eFoundations: The Repository Roadmap - are we heading in the right direction?
See also Nik Honeysett's sceptical posting on Trusted Digital Repositories. Right or wrong he encapsulates the sort of frustration we must all sometimes feel when we're looking at something a little outside our own area of obsession and wondering, "why does it have to be so complicated?" Actually that's probably misrepresenting what he's saying and where he's coming from; in any case he makes a good point: most of the time we're migrating stuff frequently, and most of the time this is perfectly adequate.