In case the product team is still looking at feedback for this idea, I'd like to put my 2 cents in on what this should have and look like.
I've created a report that actually incorporates all updates including document updates and put it in a dashboard. What helped is it's easily identifiable that the update was made against a document (highlight it!) and identify/link to the document where that update was made to. You can imagine two similar update that said, "please have a look at this document" made to two different documents, there's going to be confusion on which document was being talked about.
Also, please sort it by entry date with the latest conversation appearing first and grouped by the thread. Currently, a thread started two months ago and recently updated will still appear at the bottom, making it harder for the user to find.