This creates (drumroll) synergies with other elements of the game. Snappy, responsive movement and feedback combines with the good UI and proper* choice of scale to create that elusive "one more turn" feel. Best I´ve felt in the sub-genre since Clash of Steel. And that was in 1993.
As usual, your "PBEM" mp system is second to none in the wargaming area. (I´d chop off a... erm, fingernail, if you re-released Gary Grigsby´s WAWAWD with it implemented...

Some quick suggestions for further improvement:
- Be more liberal with the popups / mouseovers / click-for-info elements that explain rules, stats, and calculations. This really opens up a game like this for newbies, and ít´s the direction the industry is moving.
- The PBEM system is gold. But it is a great foundation to build something even better on, with stats, etc. Which leads me to my question:
*Actual question* One of my games just... disappeared. Does this mean that my opponent surrendered? Or is it a bug? Or did you detect my aimbot?
Again, fine work, keep it up!
* Personal taste of course. But it´s very hard to get a "one more turn" feel when turns take an hour**.
** I.e. "WWII at divisional scale", etc.