I would not call awk an array language. Arrays are essential in awk, but it lacks array operations. For example, in an array language, you add two arrays a and b, element by element, with a+b, while in awk you need a loop. Moreover, you do not have direct map and reduce operations, and again you need loops.

As a fan of both awk and array languages, I think that an nsl-awk would be a really interesting project.