probably what confused me the most about the data construct when I started learning it was that the examples used the same word for the typename and the data constructor, so it was unclear that they are actually separate ideas.

I think you hit the nail on the head. The use of single character identifiers--in the documentation, I don't have so much of a problem with their use for local vars in actual code--is a big barrier to understanding.

If the docs (and maybe the type signatures generated by ghci) used somewhat more verbose identifiers (typeA instead of just a or funcA instead of f or p etc.), I think it would make it easier to assimilate.