Autoeditors can currently choose yes/abstain/no on all edits of an edit list page in one go, and then change any specific vote on the edit entry before submitting. This is currently not available to non-autoeditors, who have to click on every single edit one by one to vote yes or no on, say, twenty "X performed guitar on recording Y" relationship adds. The userscript https://github.com/jesus2099/konami-command/blob/master/mb_POWER-VOTE.user.js gives this to every user, but there's really no good reason not to have this as a part of MB itself.

There's still other things in that userscript that might be useful to implement on MBS but that's a good start.