Those are technical specifications, but I think the purpose of this topic is to discuss what UDMF is for the end user, how it helps them and what can be done with it.
Doom Builder 2 will help editing in UDMF significantly even though it does not yet support ZDoom features in Visual Mode. Here is an example of what you get;
The Properties tab on that dialog contains the normal controls you know to edit the sector properties (floor/ceiling texture, heights, brightness, special effect) and the Custom tab, as you can see in this screenshot, provides numerous additional properties that you can simply set by clicking on them and entering a value or click the button next to it to help you creating a value. Note how you can simply scale and rotate the texture, set individual light levels and colors, change the gravity, etc. In this screenshot I set a double gravity (2) a 128 brightness for the floor and I'm about to set a light color for the sector.
Eventually, if people care to help me programming it, there could be a plugin that also reflects these effects in Visual Mode and even allows you to edit things like texture scale and rotation in Visual Mode.
Also, UDMF uses floating point values for vertex and thing coordinates, which allows more accurate mapping (I don't want to encourage 1 mappixel sized sector details, but it also helps with more accurate splits where 2 diagonal lines cross each other)