Ok, preliminary TUC list.
The briefing was originally about a third longer.
A further scene of the Enterprise leaving dock and Kirk jabbing Valeris for questioning his orders (again.)
Valeris was even more opposed to the mission originally. In the scene of her eavesdropping on Kirk she got a lot more of Kirk's feelings out of him.
The klingons are given a tour of the ship, where the Enterprise's equipment for gaseous study is shown.
The dinner scene was much longer and offered more lines to Uhura, Chekov, and Scotty. It eventually broke into argument.
The trial scene was originally much longer, with whole questionings cut out. McCoy would've given a classic delivery of the line "We were framed!".
Valeris questions whether or not McCoy and Kirk actually had something to do with the assassination.
Soem lines were cut about Sulu's choice to assist the Enterprise.
Martia mentions she was a smuggler and how her shape-shifting accomodated that.
A short discussion of the Bird of Prey was cut.
An alternate shot of Martia's vaporization which caused controversy, as many fans saw it in the trailer and thought Kirk was to die in the film. (More on THAT in the next list.)