So I actively dislike streaming myself, but I'm a little confused here. The whole reason we added the max weekly adds was to combat streaming. It sounds like you are using that, with a setting of 4. Is that right? As someone who dislikes streaming, I'd have trouble viewing 4 adds a week as streaming, even if they all were spot starts. But if you/your league does, you could set it at 3, I guess. Or 2. But at that point you're pretty close to just having weekly lineups. Unless the goal is that you want to allow 4 weekly adds, but not with the intent to stream. But once you start disallowing roster moves based on the intent of the manager, that's pretty hard for us to enforce.
For the record, I also am pretty avidly against changing rules in the middle of the season. In my keeper league, I pretty much won't do such a thing unless there is unanimous support.