OK, so what would I like to see by Sakai 3.0? There are a million small to medium-sized features I could list, but playing the bullet point game doesn't tend to yield excellence in learning environments. Instead, I'd concentrate on a few big things:

1. Fully integrate Sakai with uPortal, including their session management. This would both solve the "Back" button problem and go most of the way toward solving the lack of support for groups within courses. It would also allow for the creation of sharable, re-usable content containers that float free of any given course instance but can be easily pulled into any given course instance. (uPortal has very powerful and flexible groups, roles, and permissions structures. My experience with LMS's is that the designers always get these three pieces wrong because they have too narrow a sense of how they might be useful in a learning environment.) And also, uPortal is a great integration framework, supporting WSRP and JSR-168 for the hard stuff and iframes and RSS for the easy stuff.
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