I would assume the most important feature for doctors for any device UI is that things don't always change. The entire medical field selects for people with great memory, and so even if it is a bit complex at first, as long as they only have to figure it out once they aren't going to easily forget. Even if some other design is more sleek and intuitive for a first time user, the change is only going to mess up the 95% of the established personnel. Any potential tool changes need to provide significant improvements over the old stuff and need to be done sparingly.

To doctors these things are just tools, tools that they want to be able to pick up and put down 100 times a day without having to think about it. A good tool can be operated mostly on muscle memory and needs to remain static 99% of the time. Imagine if the tools a mechanic or carpenter used changed in form and function all the time. Last year they used a right handed circular saw, next year they are forced to use a left handed worm saw. Or imagine a framer picking up his hammer he has used for the last 10+ years and going to give it a swing and missing his mark, only to find out last night his boss took his old hammer and replaced it with one 2 ounces lighter and 2 inches longer and his boss refused to give his old one back. Or a guy digging through his toolbox to pull out a lesser used item like helicoils that he knows is in a medium sized yellow box, wasting tons of time looking and possibly going for a different and less ideal solution, only to find out later the helicoils were at some point put placed into a small sized blue box instead because someone else decided the old box was a bit too big and wasting space.