Yes I agree. I've always thought the 'add comment' was a bit misleading because it implies you can respond directly to that specific post, but you can't. Your comment just goes to the end of the thread, by which point there could be dozens of comments in between yours and the one you are answering! All in all, it's a bit pointlesss.
We're not all glued to GN 24/7, with fingers ready on the keyboard to fire off replies as soon as a comment appears. Mostly we are reading through threads to catch up, and then we're so often unable to 'join in' properly as we've missed that particular boat and the conversation has moved on.