Agreed. The current state of jQuery UI is what pushed me to consider other frameworks such as Dojo (which I'm really enjoying). I've also started using Bootstrap on a new project and really like it as well. I just need more components! :)
I also think Bootstrap needs an initial set of distinct looking themes. Not just different colors but fonts, padding, sizes etc. It would help me feel confident that I would be able to create something that doesn't look like everyone else's site.
I find it doubly interesting since bootstrap isn't even very good code (albeit slowly improving). Completeness, documentation and brand name really trump technical excellence here.
Either way, it's great to have one of these frameworks finally pick up steam, that's been long overdue!