The FBI has wanted this kind of power for so long that people who have worked on this issue longer than me actually have mimeographed copies of such proposals from decades ago (this was practically before the copy machine, if you can even imagine that). But Congress after Congress has wisely rejected such requests which would completely undermine our Fourth Amendment.
The FBI says that businesses would be able to challenge those subpoenas after the fact but this is slim protection -- do people really believe that the credit bureau or their credit card company is going to go to the legal expense of fighting for their privacy if the FBI goes on a fishing expeditions with their customer files. One can always hope, but the FBI subpoena would be secret forever and you would probably never know if your records were turned over to the FBI.
On a related note, in the House Judiciary Committee two weeks ago, Congressman Scott of Virginia proposed that businesses successfully challenging a Section 215 court order would get their attorney fees paid, but that too was defeated on a party-line vote. If the FBI were given the power to write its own orders for such records without any court approval, Section 215 will be phased out because: Why would they ever go to court to get an order if they can just get the same thing themselves?
Finally, I thought you would appreciate hearing about an exchange from yesterday's FBI oversight hearing. As you know, Senator Feinstein voted against the administrative subpoena request in the Senate Intelligence Committee and she questioned FBI Director Mueller again about the problems with giving the FBI such powers, absent an emergency. At the end of the questions, the Chairman of the Judiciary Committee, Senator Specter weighed in for a moment--
Thank you, Senator Feinstein. Have you convinced the director?
I beg your pardon?
Have you convinced the director?
No. But then he hasn't convinced me either.