In Boub's post about 3.3 he mentions an item called:
Hydrodynamic Flippers - Swim speed increased by 200%. / Instant
That is quite a considerable speed increase. Now the only reason I can think that such a huge increase in swim speed might be needed, would be to swim a very long distance.
Maybe its part of some quest to check fault lines opening up in the sea or perhaps its time we take a little swim to http://www.wowwiki.com/Zandalar
Anyone else got any leads on what the use for this item could be?