Once the lobby starts to work, no way that blizzard can keep up with this change without providing an alternative. With the lobby I mean any group of blind/disabled people giving rumor to this change. You have to realize wow is played by a lot of people who have little else to do due to some sort of disability. With a lot I'm not talking about 10s of thousands, but that doesn't really matter.

Imagine that a blind guy who's enjoyment it is to do a few random bg's every night with his brother, now all in a sudden gets taken away one of his main enjoyments. Making this example up, but you'd be surprised how certain people play this game and what kind of enjoyment they get out of it. Remember that iraq veteran who lost his sight during combat but still killed ragnaros in firelands? It's not only the blind people that use follow, etc etc You get the point.

Now imagine how bad of a pub it would be for blizzard when there is an article in some news magazine with a headline such as: 'Blizzard removes the enjoyment of the disabled players' You can probably come up with better titles, but again you get the idea.
Not accommodating to the unhealthy is frowned upon, in pretty much every civilized place in the world.

If you want follow back in BGs, contact some organisation for blind people, write a press statement and send that to every possible news agency in the world. Once word gets out, I guarantee you that blizz will either provide an alternative or will revert the change.