dtgreene: I happen to really like water sections in games.
It is really nice to be able to go up freely, instead of being confined by gravity, and the slower falling is a nice touch.
In fact, in Zelda: Ocarina of Time, my favorite dungeon is actually the Water Temple, and I was disappointed that later dungeons lacked any water sections. (Ganon's castle *really* should have had a water section; that would have made the dungeon a lot better.) It is really only in that temple that I felt the game actually *used* 3D to its fullest extent; everywhere else it felt like the gameplay was still mostly 2D.
Of course, there are ways in which water sections could be done poorly. I would say that Super Mario 64's water controls aren't that good, for example (though still better than that game's flying controls, which are atrocious).
Yes, water sections are fun, whether Mario Odessy, Mario 64 of Ocarina of Time Water Temple.
Even those anxiety inducing Sonic the Hedgehog underwater levels with that soundtrack are fun.