When formulas change, so must strategies. Strategies that worked for previous formulas will either a) not work at all or; b) not be as effective. Part of Utopia is adapting to changes.
War is very different from out of war, there are mechanics that have been in place for a long time that affect war gains. These mechanics were tweaked last age slightly which created a new dynamic and coupled with the revision of the gains formula entirely it's no doubt that previously used strategies will not work the same as they had before.