no one wants “disc meta”, all disc players want is a decent class. what you seem to miss out is that disc even if its the worst healer right now it still is extremely popular, thus reducing queues for SS. if disc priest will fall, expect SS queues time to go up at least 25% up on ratings < 1800.
you may ask yourself why is it so popular? because the spec was fun, now with the remake they remove all the fun while keeping all the bad design/weakness spots.
even when disc was meta, reality is it wasnt so OP it was just popular based on real data from drustavar/checkpvp. A lot of players tend to confuse the popularity of a class with its performance.
Here is a really great post by one of our forum friends, where he is explaining the current status of all the healers.