I recommend sticking to one thread. I think the more likes your post has, the more attention it will get from the ffxiv team. So keep your original thread active with relevant discussion. I also suggest changing up your original post in the other thread. Like make it short and sweet. Put in the changes you'd like to see in terms of better privacy options. Make sure your post is easy to read instead of a wall of text. And lastly, remind people to leave a like on the post to show their support. I don't think making several threads will help. One big thread with a lot of likes would be better.