I'd rather have swimming as a bonus feature rather than a whole expansion of travel and exploration like flying is.

For example, we would be able to swim in ponds and the ocean like normal humans would. I wanna go swimming on the beach in the mist, I wanna take a dip in the little lake on the sea of clouds. And so on.

I'm not saying having deep sea exploration wouldn't be cool. But doing it that way means we'd probably never get to swim in the existing areas with bodies of water. Ams we would have to go the silly lore route of having aether currents underwater