OP here: definitely the keywords-in-title have limitations as a feature set. Once I get more training examples (enough to characterize what "interesting") I will definitely look at the full text, HTML metadata, etc.
As you say, there is interesting deep stuff going on in the JS space, but there is too much average stuff for me to look at right now.
One issue I have with pure keyword filters when I apply them to e.g. RSS feeds is that they can't capture details well - e.g. I'd like seeing a detailed article about how V8 works and wouldn't to exclude an otherwise interesting thing just because it is in JS, then you spend quite a lot of finetuning the filters.