Aside from the pithy syntax compared to even the most futuristic ECMAScript, meaning frontend code is faster and easier to write (and throw away, if need be), there's another key element Clojure brings to solving this API proliferation problem, which is just how easy it is to do data transformations. The Clojure standard lib makes it trivial (dare I say, fun?) to carve up and reshape whatever data you're consuming to fit the model your application needs.
Yeah, I feel that the real innovations in UI programming are happening in ClojureScript right now based on top of React which is really a very low-level dependency. Javascript is mainly copying what's happening there with libraries that allow you do do reactive programming (like RxJS), have immutability, etc.
