What exactly does it patch?
I realized a while back that those vanilla FX that sort of add wavy movement noise to water are simply simulating reflections. They were part of the downgrade and CDPR confirmed it. Halk simply uses better shader for water and rivers from B&W expansion to enable true reflections. It does, however, reduce that wavy movement noise FX. There is not much that can be done about it. I tried to increase wave and foam strength and amount, etc. but it barely made a difference because of the actual level of reflection. Halk even created texture with entirely new pattern for waves or foam to offset that "too calm" feeling rivers and water create, but again, possibilities are limited. They are not bugs.
It would be nice if we could add more places where waterfall splashes appear, but we can't. Most rivers in TW3 don't even have collision to them.