One thing that I didn't like in Halo is that you drowned instantly in water( besides in Halo 1, you could drive vehicles in water) but I hope that in Destiny that you could go underwater and explore reefs and look at fish, that would be very exciting because I love fish and coral so I would be underwater most of the time and explore the water.
I would love to have sharks in the ocean as well so that I could avenge my grandpa who was killed by Tiger Sharks which are know for purposefully killing and eating humans. :-(
-
I never understand why people want to swim or go underwater in video games, it's always boring, would be good if we could go underwater on our shrikes though