I would love to see the multiple stages of the watering can animation be sped up. The watering can should just use the widest area quickly as possible.

I like the idea but always using the widest area possible would use a large amount of water each time. If you only need to water one square, it shouldn't use water for 9 squares.

Maybe just start with speeding up the animation and seeing if that is enough?

@mralbobo's tool charging mod does this with both the watering can and hoe, though it'd be nice to see this implemented in Fast Animations.

I think skipping charge levels is best handled by the Tool Charging mod (which is linked from the Fast Animations mod page now). Fast Animations only speeds up animations, it deliberately doesn't change any game mechanics like that.