How does this make it more useful? It’s just info porn at that point. Put in numbers because.. numbers? Perhaps if you could provide some specific examples, but this sounds a lot like info-porn to me, rather than a practical request.
What if there are hundreds or thousands? Show a thousand new posts in the email? This doesn’t make sense. I think you have a fundamental misunderstanding about what digest is for, if you want a different email that includes every single post ever made in that time interval, perhaps open a feature request for that? Or just ask users (or force them against their will) to have “mailing list mode” on?
Not sure what you mean here? Perhaps a real world example would help?
I have no idea what this means. Can you provide specific real world examples?