I surely like this idea, it can make engagement much easier and faster. While I think users then might miss out on discovering other content on the platform, it serves the user experience and that matters of course.

What I know is a worry here is compatability / formatting: I have heard from different Community Managers now that some of these replies do not look pretty on the community, depending on device or email provider that the users were replying from. So that might be a nut to crack, I would want to make sure that the experience on the community will not suffer from this (or worse, that I have to “clean up” posts constantly).

Curious to hear how the product team looks at this!

Agreed - I have seen poor implementations of this in the past in other platforms. Also things like signatures being included in the reply, not handing 2-byte characters etc. But if you can overcome those barriers I think you could boost engagement a few points.

Yes indeed.

Maybe you could also flip it around and have the users reply within a text box within the notification itself - kind of how Google does it with comments on documents. This way you could handle the formatting challenges better probably.