I used CL for many years before I switched to Clojure. And by "used" I mean really used it, not just for applications, but I also dove into CL implementations, for example I added return-from-frame (also known as debug-return) to CMUCL.

So, I kind of know what I'm talking about :-) And I don't miss anything from CL: I honestly can't find a single reason to switch back to CL.