It should go back to the real art style, the one that original game was based on.
If by "origional" you mean Unreal, not UT, then hell yes! Unreal had the best visual style of them all.
UT on the other hand tended to look more industrial and bland, there where noteworthy exceptions (that i think people tend to remember), but far too much generic concrete and metal going on in most of the maps (that i think people tend to forget, rose tintet glasses and all).
UT had some awesome maps, but also far too many that just wheren't interesting to look at, and i'm a little sad it didn't try to branch out some more into the Unreal world, some more Nali and Skaarj stuff would have been great, and it could have tried to introduce us to the Krall and Mercenari worlds aswell, a missed oppertunity i feel.
UT2k3/4 added back some more variety, and some more excotic alien stuff, which was good, there wasen't as much bland indus over it, but something about the colours just wasen't quite right, leaving the game with an oddly cartoonish look, a good effort but flawed exicution.
Personally i could look past the cartoony and enjoy it for what it was, but i can certainly also understand why others felt it detracted a lot from the game.
There was also too much disparity in the themes, i applaud giving players something to choose from, it keeps things interesting, and in a game like this Dev's have an excellent chance to do just that, but you can also take it too far, like adding space egyptians, now that's just silly.. and some of thease themes, like the Genmokai stuff, just wasen't propperly realized, it needed a little something more to really bring it to life, it lacks that X-factor that made us interested in the Nali and Skaarj worlds.
UT3 is.. well its GoW meets WRF meets HR-Geiger, as seen through a used coffee filter by someone who's eyes cannot adjust to light.
People who like that exact combination of mismatched things is a pretty narrow demographic to aim at i'd say, and you have to wonder if "dark and ominous 24/7" really is the best theme for a fast paced arena shooter, and especially one like UT that has never before tried to take itself too seriously.
As you may have guessed, i don't really care for this theme, and unfortunately, UT3 only has that one look, even the Asian theme, which is the only one that stands out a bit, still conveys the same atmosphere, so it's 100% hit or miss if you like it or not.