Don't tell us you're quitting Eddie!
Just change strategy in light of new game rebalance. If it's too long to retrain for a suicide mission, maybe it's time to move to 4-5 starring army to take your troops home and retrain only a few.
French is still the best for suicide mission sniping TC, as it still retrains faster than any other nation.
But if you go mixed army 4-5 starring route, there are many viable choices, depends on personal preference and techniques. Romans, Germans, Koreans and British all have unique abilities for mixed army strategy.
I've taken a 5 day peace treaty to let things settle down and observe the new meta game. I'll see afterwards what to do. But I think it's a bit early to think about changing nations, I'd wait a little bit more.