I think a super useful benefit for subscribers would be the ability to see absolutely all, or at least a vast majority, of the HITs a requester has posted over the last 24 hours. I like seeing if a requester is active 24 hours a day or if they're only active during the day or night. But if a requester posts a lot, it's not possible to see how active a requester has been over the last 24 hours unless you stay up for 24 hours and refresh the page every now and then. I feel like some others would find this extra benefit useful too. Or if some requesters post too much for this to be possible, at least increase the limit of the HIT history from 10 to something like 100 for subscribers.
This is mostly the problem, FWIW. The database table holding that information is a huge drain on the site, and I need to sit down and fix it before I can implement anything like this. Will not put any of that behind a paywall though, it'll just be implemented if it's feasible to do without destroying the servers haha.