Some research ideas in forecasting

Nice post! I'll throw another signal boost for the Metaculus hackathon that OP links, since this is the first time Metaculus is sharing their whole 1M db of individual forecasts (not just the db of questions & resolutions which is already available). You have to apply to get access though. I'll link it again even though OP already did: https://metaculus.medium.com/announcing-metaculuss-million-predictions-hackathon-91c2dfa3f39

There are nice cash prizes too.

As the OP writes, I think most the ideas here would be valid entries in the hackathon, though the emphasis is on forecast aggregation & methods for scoring individuals. I'm particularly interested in decay of predictions idea. I don't think we know how well predictions age, and what the right strategy for updating your predictions should be for long-running questions.

Any forecasts of any number of experts in any domain out of normal distribution (where you do not need experts, you need statistics) are worth of nothing and do worse than coinflip (in binary outcomes). You cannot predict anything in more or less complex systems except that they will change suddenly at some point of time. 

(may I pls do not write IMO every time, because all I write is not truth, but only my opinion) ))