Heroes 5.5 WarGame Edition - Tactical Edition.

Ultimately, dragon enhancement boils down to duels (this is the most significant limitation). The fact is that in dueling armies, units are selected to be equal to one ED (an exemplary dragon). And increasing their numbers due to the enhancement of 1 dragon (and, consequently, 1 ED) is not good for gameplay. The most interesting battles, from the point of view of tactical nuances, occur precisely with small forces. When you attack tier 6-7 creatures without a guarantee that anyone will die immediately, and you need to finish them off, focusing your attacks.

Added 4 minutes later

It all depends on the size of the map. Sometimes you just need to get there and not lose your castle to the opponent from behind.

A preliminary benchmark is 3 days of travel between starting cities (along roads). Whether longer distances will be supported is difficult to say in advance, before testing.
The logic is very simple: the closer the players are, the more interaction there is between them, and the more strategic the game looks (player against player, and not against the map). But at the same time, some time must be left for exploration and reaction, so that the game does not boil down only to rushes.

Logic.
Someone has developed according to this system.
And someone was a week late... everything is over. The first one wins...

Logic. Someone came to work on time, and someone was late and only came in for lunch (1 week is roughly half the game). Which of the employees will be fired?

Between players of equal level, the score should be kept in days; a gap of a whole week is essentially a demotion (the destruction of a weak player by a strong one); there should be no struggle here.