Wouldn't it be cool if we could just find random items or easter eggs underwater? Or maybe references to times past (i.e. sunken ships, bones of adventurers). I think Oblivion was really lacking in this respect. While it doesn't matter either way, it'd be a great addition.
Definitely! Morrowind gave a lot of opportunities to put swimming skills/talents to practice, and it certainly gave the game world a greater sense of depth (literally and figuratively), but i agree that the opportunities in Oblivion at least seemed far fewer and less important- the "water breathing" spell for example was hardly ever needed.
I am pretty sure it has already been confirmed that the underwater environments are now as detailed as the landmasses. If forget which article touched on it can anyone supply a link?
Good to know.