Defender's advantage in battle

The defensive player having the initiative will actually improve his chances of survival. However, this would make the battles even more dependent on numbers, which in the end would increase spending on the production queue (industry) to start and maintain a war. Soon players would tend to maintain a more peaceful game, decreasing the usefulness of military and expansionist cultures.

In my opinion, if the battle map (gray zone) accentuated the relief of the world map, favoring tactical battles, the impact of the initiative would be mitigated, as a good positioning is easily could nullify the enemy's lines of attack, something very rare on maps that are usually mostly flat and open.

Not sure it  would make sense to negate initiative on the attackers side.

A compromise would be to differentiate between :

- defending army has not moved this turn : gains the initiative in combat if attacked

- defending army has moved : loses the initiative and is open to counter attacks