Is it possible to modify the ruleset so as to change stack destruction?
Solution 1:
If you are launching your own game of Freeciv you can play without stack destruction. When you set up the game you can pick your preferred Ruleset Version, and the select More Game Options.
In the Game Settings window navigate to the military tab and deselect the rule Do all units in tile die with defender. Just click apply and you are good to go.
