Replying to news posts: No. Updates are often posted in the form of news comments made by andrew, those would be very hard to find if everyone was able to comment on them. Discussing on a dedicated news discussion thread in the General Discussions forum: Yes.
-1 News/Announcement posts are just that, not discussion places. Sure it makes another thread for a discussion place but really... most of the replies will be trolly and if some one has questions/comments/whatever they should care enough to make a second post in the appropriate place.
But what's the point of making a new thread when one is already made for the newspost? It's not fair to argue that most of the replies would be trolly as we do have forum rules and staff members to deal with that, and most members of the server would just post their thoughts on the update or a thread. It keeps all of the questions, comments etc in one place for anyone to read.
Users are absolutely welcome to discuss any and all news posts in the General section. The news section is for news, as well editing news posts would not bump them to the top and bring attention to them. Won't happen, sorry.