The fact is, though, jQuery and Dojo are the two libraries with which I am quite familiar, and so they are the two libraries I am most able to compare. Having used both, it is easy to see the weaknesses of ... both! I truly believe there is a "jQuery divide" -- there are people who think jQuery is what there is to know of JavaScript, and that it can solve all of their problems; then there are the people who know there is more, either because they have always known or because, like me, they've discovered it through some painful mistakes.
What I am asking for, in this post and in my Berlin talk, is for the people who know there is more to take some responsibility for bringing the others up to speed, to show people what can be done if you leave behind the "get some elements, do something with them" mentality.
None of this is to say that jQuery is not a useful tool, and the right tool in so many situations! I have used it, I have contributed to it, I have taught it, I have recommended it. Its API is seductive and its API is a huge contribution it has made to the JS landscape. The point, though, is that it's just an API -- an API that can be and has been be readily replicated. My experience has been that other libraries' APIs can have their own elegance, once you get used to them. The problem is that the appeal of jQuery's API I think is what can lead people to keep approaching problems in a DOM-centric way long after it makes sense. I do not fault jQuery for this, but I think as a wider JavaScript community we do well to discuss -- and not in an us v. them way! -- other viable approaches that exist.
Finally: Backbone is a viable entry in the field, and I am eager to see more complex examples (to-do list applications fall far short of this) that use it. I haven't used it personally, but I mostly like what I see and have heard good things about it. Unfortunately it had just come out right before my Berlin talk, and while I may have mentioned it in my actual talk, it isn't in the slides. (That said, I do cringe a tad that its examples suggest (http://documentcloud.github.com/backbone/#Model) that a "Sidebar" is a thing that should be a model.)