Tongue in cheek: "Unlimited Data Plan Still Exists" and it exists with no throttling, its called their Limited Data Plan. Once your high speed data cap is hit, it charges you again. You can do this an unlimited number of times, its what makes their limited data plan Unlimited.
Seriously though: For those of you who do not understand how wrong the above is, many of us joined an unlimited data plan so we can keep a budget. Many months we do not ever hit a cap; however, if we ever do it is just wrong to hit us with any amount of a cap. We're paying for 3GB of data each month when we only use less. By throttling us, it is as if we have the right to say well AT&T I am going to throttle the fee I am paying you. I have an unlimited account and I only used 500mb this month, so I am only going to pay you $15 not the $30 we agreed upon. As a matter of fact, 95% of the users do not hit the 3GB cap; therefore, you need to give 95% of us some of that $30 back for every month we did not hit any cap.
The purpose behind unlimited was so we could give and take, we use less some months but we use more others. By removing the capability to sign up for it again on the iPad's, you have forced us down this path of keeping it active continuously. If you ever throttle my iPad, I will goto small claims as well.
Think of it like you're buying insurance from them. Peace of mind to not have to worry about going over. The extra fees you paid for unlimited is peace of mind insurance