We are basically saying the same thing in different ways... The script would spawn new troops at a certain periodic rate. One that has to be play balanced. If you put that in the AI will sally out sometimes when it thinks it can win.

The other thing that DLV has is a siege "cost" script. It cost a lot of money to lay siege to a city. So if it's going to cost you an arm and a leg every turn you extend your siege you are more likely to assault it.

It's really just thinking of ways to fight on the neato battlegrounds from the campaign map..

You want to fight siege battles where you assault and when they sally.... What's that saying "Variety is the spice of......something."