That’s changing, though we don’t know quite how just yet. ArenaNet posted this morning that it’s pushing out the planned balance update next Tuesday on May 8th, and with it, big changes to underwater combat too.
“The next Guild Wars 2 balance update arrives on May 8, bringing a sea change to underwater combat! We’re enhancing underwater skills and utilities so you can blast the barnacles off anything that tries to nibble your toes while you’re swimming. Keep a lookout on the morning of the May 8 balance update—we’ll publish a developer blog post that wades through all the details.”
Reddit is somewhat baffled by the announcement, guessing so far about new rebreathers and new maps (presumably the new fractal) with underwater content.