I found them to be archaic, but workable once you got used to them. Basically the same as System Shock's controls. I could see the game being massively improved with a mouselook mod like the one for SS.
UU controls were nothing like System Shock. Systems Shock was clunky at best, and that "click on the body to have a stance" thing gave me cancer. The mouse control was simple in UU, I really don't know what problems people have with it. Hold mouse button to walk. Walk + right click to jump. Hold and click to use item. Hold and swipe to use object in the world. Click to examine, Talk. The only thing you needed the keyboard for was to switch into combat mode, and to play the flute Then it had the same mouse swings as Arena and Daggerfall later re-used.