Agreed. The idea of triggering emails on edit after X minutes/hours is pretty nice.

But I've an improvement, which stems from my Reddit usage.

One thing I noticed about reddit is that they don't really give attention to this issue, which really only matters with emails, as notifications are able to reflect the most recent item's text. I tend to edit my posts quite a lot, usually within a short time frame ~5 minutes. Be it grammar, a mistake, or just addition of content. So here's the idea: Wait X minutes after the last edit and then trigger the first email. Email tends to not be a call to immediate action anyway; notifications could serve that purpose.