Laurent Romary and Chris Armbruster have self-archived "Beyond Institutional Repositories" in SSRN.
Here's an excerpt:
The current system of so-called institutional repositories, even if it has been a sensible response at an earlier stage, may not answer the needs of the scholarly community, scientific communication and accompanied stakeholders in a sustainable way. However, having a robust repository infrastructure is essential to academic work. Yet, current institutional solutions, even when networked in a country or across Europe, have largely failed to deliver. Consequently, a new path for a more robust infrastructure and larger repositories is explored to create superior services that support the academy. A future organization of publication repositories is advocated that is based upon macroscopic academic settings providing a critical mass of interest as well as organizational coherence. Such a macro-unit may be geographical (a coherent national scheme), institutional (a large research organization or a consortium thereof) or thematic (a specific research field organizing itself in the domain of publication repositories).
The argument proceeds as follows: firstly, while institutional open access mandates have brought some content into open access, the important mandates are those of the funders and these are best supported by a single infrastructure and large repositories, which incidentally enhances the value of the collection (while a transfer to institutional repositories would diminish the value). Secondly, we compare and contrast a system based on central research publication repositories with the notion of a network of institutional repositories to illustrate that across central dimensions of any repository solution the institutional model is more cumbersome and less likely to achieve a high level of service. Next, three key functions of publication repositories are reconsidered, namely a) the fast and wide dissemination of results; b) the preservation of the record; and c) digital curation for dissemination and preservation. Fourth, repositories and their ecologies are explored with the overriding aim of enhancing content and enhancing usage. Fifth, a target scheme is sketched, including some examples. In closing, a look at the evolutionary road ahead is offered.