creating a modern implementation from scratch and it gaining some traction, basically what Clojure did for Common Lisp

it's not a new implementation - it's a fully incompatible new language. Zero CL code runs in Clojure because the operators are incompatible/different and any existing CL code needs to mostly re-architected, since Clojure has a very different approach (more functional, less object-oriented, less state, lazy data structures, no linked lists, hybrid libraries /language partly using hosted language, ...).