I started even simpler than that. I started by just eliminating stopwords and count the frequency in each word in the document itself. I did not use a set of documents as the goal was for the algorithm to be used on the spot for a single block of text.

A few months later and after many iterations + a whole lot of testing, the algorithm now can extract super relevant keywords 90%+ of the time!

I wish I knew about the WikiCorpusExtractor. Thanks for the link!