Clearly deep-diving didn't work, though (unless you count diving all the way to the bottom, forever, as the large majority of u-boats did

)
Dive times... yeah, u-boats were faster on average, but in the fleet type books I've read (written by the skippers or crew) they were aiming for 30-something second crash dive times.
I actually agree the fleet type would not have been as effective against the allies by a considerable margin, though I'm a little at doubt as to how much worse it could have been than the u-boats. What % of u-boats were sunk? 90%? There's really not much room to do worse than that, and even if the fleet type WAS worse (probably true in the ATO, I'll grant you), it only had a few % points worse available to it. So if the u-boat was not at least that much better than the fleet boat in the PTO, the fleet "wins."
Get what I'm saying?