The Ultimate World War Two game does not exist, yet. The ultimate game would be a combination of three concepts: a grand strategy, tactical play, and massive multiplayer online [game] play.
I envisage being able to jump into the position of command military officers of any rank, or into political positions which determine the strategic course of a country. I want to play the personality. Play Rommel, a Field Marshall, or a line Captain. Issue orders or directives to underlings. Follow orders from above to achieve objectives.
A hierarchical AI would play every officer or politician and players would jump in, replacing the AI unit with themselves. Something like Mr. Smith in the Matrix.
Strategically there is a game approaching this concept. It is call Hearts of Iron III. It is in its third iteration. Needs another couple of development re-thinks to get there so maybe by Hearts of Iron V it will be conceptually ready.
Tactically there is a game called Command Ops. It is almost as low tactically as one would want to go. Any lower and one just has an idiot "shooter" game (know as a First Person Shooter; FPS). Command Ops also needs a few evolutions of development. Its graphics currently suck, information feedback is archaic, and contextual play is virtually non-existent. Still, it is trending in the right direction.
Both games need to tie into geographic databases. They need to incorporate sparse matrix theories getting referencing down, in stages, to the 0.1 km gold standard all the while reflecting different command interfaces. And they need to use a global referencing system (azimuth angle, polar angle, and vector distance) for referencing game units on the variable surface of the Earth and above it (even below it).
I see the perfect game as evolving only by both companies merging with one of the big FPS companies who will see it as a big revenue generator. Revenue generated by people purchasing time as game personalities.
That's my perfect game ... well, perfect if it was free.