One thing that I see slowing down real teams building real web stuff with Clojure is the near-dogmatic desire to compose (dare I say hack) everything together from tons of libraries that each have their own understanding of how things should be.
I bet Clojure would be much more popular and nicer to work with if the community would _also_ (i.e. in addition to the current approach) have actively-maintained, batteries-included, generally usable web framework(s). (Is Biff it?)
So that there would be alternative path to choose for us who like the language, but are not fans of the build-your-own-monster approach.
Disclaimer: I have been spoiled by Ruby on Rails