The swimming animation really needs some tweaking. For example:

• When sprinting and falling by accident in one deep water, you go into the swimming animation. This makes places like shown in the screenshot a nightmare to travel in. Besides, in real life, you would hurt yourself when you dive in undeep water like this.

• While sprinting in water, it's extremely tricky to get above water for air. The animation makes it look like you are barely unable to make it out of the water.

• While sprinting in the water, it takes a bit too long to get up one block. You have to "glide up" it before you can attempt to get over one block, or stop sprinting.