Uh oh, I am way too sleepy to give you a comprehensive list. Basically, the advanced features you are asking about, turn on the most "boardgamey" features of WW1, namely the I go - you go mode.
Someone will explain in detail I am sure.
However, I advise you to stay away from this mode in single player for the time being. Calvinus mentioned it somewhere that he has started heavy bug-hunting on it, but you can still run into the occasional AI hangup with it (changing how the AI works to solve compatibility problems post-release did not help this advanced game mode).
Besides, the AI's performance in general is lower (in this advanced game mode, you have to decide in which order to activate your armies, and the AI can not always chose the optimum order, nor can a human in all cases, mind you!).
Plus, by many ways its less realistic than the standard move mode.
All that being said, the advanced game mode would be my choice of game mode for multiplayer matchups.
