Adding bottomless pits and drownable water solves several problems.

* Since drowning water must be walkable, it will no longer stop Octorok projectiles and other such things from passing across it. It also eliminates the not-so-logical dipping-into-water delay.
* It also allows the quest maker to use pit combos that both the Ladder and the Feather can cross. Or pits that require jumping off the Ladder!
* And thirdly, it eliminates the use of pit warps, damage combos and extra screens that are currently used to simulate bottomless pits.

In fact, I've already got the basics laid down. In the coming builds the "Can Drown in Walkable Water" quest rule should be available. (Note: I don't control the release of builds, so don't expect it tomorrow.)