There are two possible conclusions from your data. One possibility is that the court became more strict after 9/11. The other is that the agencies tried to push the court further to see what they could get away with. Offhand, the second one seems more plausible.
So, 97% of the requests were approved as is, without modification. This is an "unprecedented" rate of rejection? What's the number of annual requests that were approved, as compared with previous administrations?
I think there is a third possibility, however. That SOME on the FISA court don't really understand that the WOT is a war not only for our survival as a country, but as a civilization.
EVERYTHING changed after 9/11. Just like the British lost the Revolutionary War because their antiquated "rules of engagement" were no match for the guerrilla warfare America was waging, so will we too if we don't approach this enemy differently than we have other enemies in the past.
But somehow I think I'm talking to a brick wall here...