The categories of stuff on LW as I perceive them (in no particular order) are:

Philosophy

-Values and ethics (human, utilitarian, alien, or otherwise)

-Game Theory (subset of instrumental rationality)

-Epistemology (epistemic rationality)

Activism

-Effective Altruism (Givewell, 8000hours, meta charity)

-X-risk reduction

-investment in far future

Personal Development

-happiness-boosting

-Fighting Akrasia (procrastination, motivation, willpower)

-optimizing your organism (body, mind, nootropics, supplements,exercise, etc)

-good habits and heuristics (especially organization, decision making)

-tools and educational resources

-bias recognition and reduction

Self Referential

-about Lesswrong and associated blogosphere

-book reviews and views of various philosophers

-rationalist fiction, especially hpmor

Checking back, they line up well with yours.

However, as someone who is interested in all of these things, for me a more pressing problem is: how can we collate past content so that it will be easy to access now? There are a lot of great posts that aren't in the sequences, that I don't want to spend lots of time digging through and finding.

I think most people interested in one LW topic tend to be interested in others, so I'm not sure how much creating separate subreddits will improve anything.