I don't think there'll be too many changes to groups. People still have to willingly join a group, and it already bases group notifications on how much you engage in the group (if you comment/reply a lot, you'll see more notifications in your feed for that group)

I actually think the recent announcement of changes to Facebook was a huge non-announcement. They basically just said they'll be doing what they announced back in 2012, or whenever it was that they did the last major algorithm change.