Keychain is the most important feature. Next up, I would like to have a way to use downvote control, without giving away my posting authority.

How would you do that ? Like a dashboard where you have a list like "posts that matched your criterias" and on which you can manually downvote via keychain ?

Meanwhile you can always run your own downvotecontrol instance, it's open source :)

Also, is it checking how big the downvote has to be in comparison to pending rewards, so the downvote isn't overkilling?

This is part of "Voting mechanism overhaul"