1) Cruft on all landing pages and having to click through to get to the comps page which is the site.
2) Annoying focus on exploratory notebooks. Inevitably they aren't powerful enough and people link through to external sites.
3) Forcing the use of 3rd party compute platforms to enter comps. Half the fun for me is messing around with my own ideas and this just gets in the way. These should be optional rather than required.
4) Poor incentives. Many of the comps have tiny prizes for the value of work that gets done. They're also concentrated way too much at the top. Unless there's something I want to try out, the expected value of participating is way too low to do it just for the giggles.