J seems ideal for quick calculator pad. For that, we mostly are relying on its base primitive and standard packages. It is not much trouble to memorize and internalize idioms.
If we are going to accumulate our own set of libraries or develope complex systems, we are devoloping vocabularies and the library/code we develop is like the definitions to the vocabulary. In this case, I am not sure the succintness that is close to crypitic is virtue. When we use vocabulary, we don't really need carry definitions around. And when we need check definitions, don't we desire simpler more verbose descriptions than cryptic ones?
Since its main attraction is in the expressiveness, I don't understand why they don't investigate in a better visualization. It already defaults to an IDE-type of editor, so why not make the symbols and layout more look like math?