Ignoring API compatibility and speed etc. (numcl doesn't talk to BLAS/LAPACK IIRC), even the basic datastructure isn't quite there. Numcl uses fixed contiguous lisp arrays as opposed to the strided ones that are standard in Numpy.
P.S- There are atleast 5-6 attempts to build something of the sort starting all the way back from Matlisp, and none of them are feature complete.
It's been done. I have no experience with it but a numpy clone in CL exists.
https://github.com/numcl/numcl