Can single-key shortcuts finally be changed/disabled? I can't count the number of times I thought I had focus in a different element or even different application and accidentally archived, marked as spam or otherwise hid several e-mails just by a typing a single word.

I'm afraid that's just because spammers, trolls and other bad agents haven't discovered this platform yet and/or there's not enough people here for spamming to be worth it. The current selection of users who were likely to join also probably has an effect. Once (if?) this grows and reaches more general population, I'd bet it will look similar to /r/all/new.

Edit: It's a kind of paradox. You want more users on the platform so that there's enough content and more niche communities can form but that inevitably makes the place less pleasant. Although this moment is still very, very far for kbin. I mean Reddit became absolutely humongous in the last several years.