In WW2, the locations of sunken ships were better tracked, so it is easier to find them. Plus ships of that era were rather large and made of metal, so they are easier to find with sonar and magnetometers.
I suppose you could look for WW1 wrecks, but most of those will be in the North Sea, have already been found, and are probably draped with years of tangled fishing nets (I know the Lusitania is covered in snagged fishing gear). Maybe the remains of the British fleet that got sunk by the German Asiatic fleet off of Chile have yet to be found, and the remains of that same German fleet that got caught by British battlecruisers off of the Falklands.
It would be great to see the wrecks from Trafalgar, Quiberon Bay or many of the other battles from the age of sail, but the wooden ships have A) rotted by now B) might have been salvaged/looted for cannon and other valuable artifacts and C) buried on the ocean bed by years of sedimentation and deposition moved by currents.