Not only don't I have a problem with this, I am glad they are doing it. I for one was a bit tired of subsidizing those who seemingly used AT&T (or whomever) as if it was a wired broadband ISP. And don't kid yourself, those top 2% using the most data--by far--would not have been able to exist without those of who did not use nearly as much. But unlike insurance we all paid the same price? Something had to give and it started last year with the removal of unlimited plans. Now the extreme users are really standing out and the other shoe is soon to drop..= Really should not be a surprise at all.
If you want to blame someone blame the people who hung onto the term "unlimited" as if it was a ticket to a race to consume as much data as physically possible. Torrent downloads, non-stop video streaming on 3G, tethering a laptop 24/7... you name it. All on 3G that is not as robust as many seem to think.
In the four years I have owned an iPhone, let alone the years of smart phones before I got it, I have never used more than 1.4 GB of data--and that was one month. It's not that I was frugal on 3G data either. I never even really pay attention to how much I use--but I know I use my iPhone a lot.
Anyway, I really don't see this as a problem for even unlimited users using 4GB per month. I suspect the throttling won't occur till you go over 5GB--by how much I don't know.
Michael