The FISA judges are concerned that a warrantless wiretap might be the sole basis for "probable cause" that justifies a warrant, which would amount to bootstrapping an possibly unconstitutional surveillance into a constitutional one. It's a valid concern, given SCOTUS precedent (See e.g., "Kieth").
The judges don't want perps going free on a technicality, and they also don't want to put their imprimatur on a process that violates the Constitution.
The solution is to get Congress on board with a stiffer surveillance law. That way, "we the people" will have signed up for the intrusion. Comparisons to WWII are approrpiate, I think. The powers granted by Congress there were sweeping, and included censoring of mail, etc.
I disagree. And I think the judges who leaked should be impeached.