How much credit do you want to give the USN? As far as I'm concerned, the Titan was found at a expectable rate with a blind search given its proximity to the Titanic. The Titan was found 1600ft from the Titanic so a 1600^2 area (at 100 sq/ft s; The Odysseus has a 4k camera after all) would take 7 hours so finding it within 4 hours seems entirely plausible even if you just did a blind search starting from the Titanic. But also if you knew the exact location it wouldn't take you 4 hours to find it.

But my original point is really we already have estimates of MH370's location even without using secretive methods. It's just going to be a lot harder because knowing where on the surface it crashed doesn't tell you where it'll be below the surface.