People who like APL do not often code with readability as their number 1 priority. In fact, to code in APL one must have an outright disdain for the idea that someone else could easily understand their code.
No, we just have a different idea of what's readable. APL was created to have a mathematical notation that made problem solving easier. Don't believe me? See Iverson's Turing Award lecture,"Notation as a Tool of Thought" (http://www.jsoftware.com/papers/tot.htm).
"I did pure mathematics in school, but later I was a teaching assistant for a graduate course in computer algorithms. I could see that the professor was getting killed by the notation. He was trying to express the idea of different kinds of matrix inner products, saying if you have a directed graph and you're looking at connections, then you write this triple nested loop in Fortran or Algol. It took him an hour to express it. What he really wanted to show was that for a connected graph it was an or-dot-and. If it's a graph of pipe capacities, then maybe it's a plus-dot-min. If he'd had APL or K as a notation, he could have covered that in a few seconds or maybe a minute, but because of the notation he couldn't do it." - "A Conversation with Arthur Whitney" (http://queue.acm.org/detail.cfm?id=1531242)
APL is actually not inherently so bad, because at least the operators have some vague relationship to what they're doing and are all distinct. I can't read J at all because in attempting to embed the APL operator space in ASCII they went in for multiple token operators that can be modified (so =, =., and =: are all different, and actually quite different IIRC).
A better way of doing this is Fortress, which tries to use mathematical notation when possible but doesn't try to compress it as small as possible.
