I propose that each city can only have a certain amount of defenders as a maximum. The reason for this is that a new player can very easily get into the game and some cities because they know their attack will be successful.
My idea is that a city can sustain 0.5% of it's population as defenders. So a 1,000,000 population city can support a defence of 5,000. As the city's population increases the effect of this limitation basically disappears because at the moment 10,000 should be enough to win most (except mine) cities on the map.
It should mean it is not worth a larger net worth player fighting smaller players to hold on to a smaller city.
Bonus cities could be exempt from this rule.
This feature will need to be intergrated after the merge/split armies function is integrated though because you could attack a 1,000,000 city with 15,000 troops win and be left with 10,000. 5,000 would stay in the city and 5,000 would automatically be split into a new army and be sitting outside the city awaiting new orders.
Thoughts?
blitzkrieg