WW2 lasted from between 1939 and 1945 if using the European context of the term WW2.
Leaders made decisions daily in real time and often after lengthy negotiations with other world leaders after having travelled hundreds or thousands of miles to meet.
Matters of grand strategy were often worked out with elaborate staffs working for long hours sometimes night and day.
Not one single crucial meaningful decision was made during "5 minutes".
Thus, a timer is not a useful option, it is a dumb option, as it neither reflects in any fashion what it was like to command the forces of any nation then at war, nor impose any useful means of determining if my decision making processes were on par with the then world leaders.
Being able to allocate my resources, decide the options for my many units, judge whom to attack and where as well as when and in what order, is therefore something I want done right, with the same potential for careful thought and reasoned contemplation as might have been given by the actual historical participants.
If you want a genuine option, one Hubert can code into the game, something that adds to the experience and actually reflects the actual conditions of a war, then you want the computer to simulate lieing and deception.
Every now and then actually tell you a unit is at one strength level, when in fact the truth is it is at another. Lie about a unit's position, such that you thought it was there, but really it wasn't.
Currently, I have not played a game that actually models espionage that I know of other than Civilization, where you can insert spies to mess with the oppponent forces.
Wouldn't it be cool, if all your hard work was ruined by the computer using an all to human trait, and simply cheating
But timer's nope, waste of time, and that is all it will ever be in my opinion.