It's been asked for so many times, and it's not as if people are asking for the new UI to be scrapped; it has its merits.

♦The new UI takes up a lot of room on lower resolutions
♦The new UI has buttons on all sides of the screen; it's harder to navigate
♦You cannot see how much health your team mates actually have; you can see how much relative to their full health, but they might only have 8 out of 10 pips
♦It's hard to see your own health; your vision is focused on your character on the centre of the screen, you now have to look to the top left corner rather than slightly down
♦There are some redundant features; the giant self portrait, your knights's rank and name (why??) and some would argue the shield bar that eats even more screen room
♦The UI may have been reworked for battlesprites, but since sprite moves simply are placed beside vials, sprite moves would've fit with the old UI

And then there's the small things: you can't see your crowns when playing, you can't see what weapon you're currently using, the UI is very shiny, pills and vials look out of place.

And you know what's the most depressing, there's a hud folder and a hud V2 folder in the SK files. ALL the files for the old hud are still there, so there aren't really any reasons, that I can think of, preventing them from letting us switch between.