to negate the power of the fs they should just make killing take more turns and it easier to wall. instead of lowering the turns just make it take more turns to kill. just tweek the formulas so instead of killing in 200 hits it takes 300 hits. that has the same effect as lowering the turns we have. then make it so you can regain population easier when you have low pop and slower when you have more pop. there are times where you run a turn and get 40 pop and they can kill all that with one attack and then when you get real low that 40 pop is 4-8 hits.