OK these improvements would almost make a perfect console editor.
1. Lighting...street lights/placeable light objects or light balls. ( they dont have to be amazing dynamic lights either just enough to light up a area )
2.Weather controls sunny to stormy.
3.placeable sounds within range...animal forest sounds to busy city sounds (example)
4. placeable fog patches
5. Square/rectangle object editor...either a square tile that has different texture choices ( brick/white concrete example ) or a slew of random walls with a certain texture on them like brick or gray building tiles. To be built up into whatever kind of building you want ( maybe even a color wheel? )
6.teleporters of some form ( trust me )
7.Adjustable water heights or if nothing else placeable water falls ( you dont have to always see above the water fall )
8.bigger map making area?
9.like someone else said elevators, activating switches to things, stuff like that.
10. AI even if there dumb as long as u can face them in a certain direction and when they see you they attack you thats all we need to make some amazing single player maps.
11. Scripted events ( things like when you walk into a certain area where you placed a marker for a scripted event you can have an object that you selected spawn or something like that. Example you walk over a large hill and hit the marker all a sudden 100 exploding barrles bombs or whatever just spawn in the sky and fall the ground way out infront of you. It would look like a huge war is goin on ) just an example.
12. atmosphere changer ( kind of like halo 3s that can make either a old western looking map to a dark creepy map.
Those are a few things that would expand upon FC2's editor in so many amazing ways. Im sure ill think of more after I post this but, if there good enough ill add them to the list.