3 things

Ladder, lift, swimming in water! These three things Please put them in the editor. Thank you. 

These exact three things were already requested here.
They're great ideas, and I'd love to add them at some point, but they aren't all simple to add.

Because everything is tile-based, there may need to be four different ladder modifiers (one for each side of the wall), or maybe it could be done in a different way. Overall not too difficult and might be coming soon.

To add lifts, you'll need to specify a start and an end height. The editor currently has no way to 'link' tiles in this way, or allow for per-tile properties. I'm probably not just going to add a bunch of (+1 lift, +2 lift, -3 lift, -4 lift, etc..) modifiers. Also what if people want to change the speed? That'll need to be supported in a way that isn't complicated.
Any moving platforms in general will also require modifications to the movement controller, to ensure the player always moves smoothly with the lift/platform.

Swimming will also require a lot of changes to the movement controller to allow for floating movement. You'll also have to consider how water tiles can be placed, and if/how their height could be adjusted, whether it's a damaging toxic/hot liquid, or depletes an oxygen meter.

It takes time to plan, design, and implement these things in a way that's easy for anyone to use.
If any of these things are too complicated, the engine will be less approachable for new developers.