A user interface for a game is like a doorway to a treasure room.
There's treasure in there! That counts for a lot; you'll tolerate a door that doesn't work too well if the treasure is tasty.
But there's a limit (SWIDT) to that. A door that's not just poorly hung but that actively prevents you from getting to or enjoying the treasure is is just too irritating, and most people will reluctantly (and maybe noisily) go look for treasure elsewhere.
To further belabor this analogy, what Josh is building is more like a gateway construction kit. Spending another week on this should yield a system that will allow not just Josh but modders to create interfaces that:
- provide the basic functions (windows, radio buttons, checkboxes, scrollbars)
- are responsive even when there's a lot of them on-screen
- are simple to understand and apply from a dev perspective
- are simple to understand and use from a player perspective
- stay out of the way unless the player wants/needs them
- are highly configurable (SLIDERS!)
- are easily extended (functionally and visually) because the code has been well-factored
- can talk to each other through a consistent interface
- adapt dynamically to any resolution and aspect ratio (4:3, 16:9, 16:10, widescreen)
- are most likely future-proofed for post-launch game enhancements
- look pretty!
That might look like a lot of coding goals, but it's pretty much the bare minimum feature set (other than that VR thing) for a game that's going to be supported for X amount of time after it's released. There might be more.
As amazing as LT-the-game is set to be, it would be a shame not to give it a UI that addresses most of the goals listed above, so that players aren't discouraged from exploring the actual gameplay features.
That said, I sure hope we're not looking at more than another week or so to follow The Other Path for moving the UI system into the core. As Hyperion rightly says, functionality (though, I would add, with at least one eye on the future) is what matters most right now.