Ocean mob and movement update

I would like to see an update to the oceans. As it is now the oceans and very safe you can even afk in a boat and be fairly sure you will survive. I believe greater variety of ocean hostile mobs along with some more flying hostile mods would make the oceans more difficult. Now you would also need to improve the players ability to defend them selves perhaps with a bigger boat or a harpoon on the boat or both. An increased variety and use of passive mobs would also be nice in the oceans and rivers. O large Whale like mob could be very awesome and maybe giant squid. Imagine being able to use a whale as a mount. Some mobs could spawn at different elevations also. Meaning some mobs could be hard to find and harder to encounter.