sounds like a terrible idea. why continue to play if when you actually reach that sort of size you just keep losing troops that badly. They need to bring down the advantage the weaker defender gets if they continue with this.
sure, you could just spam troops, but then you just keep losing resources. This is supposed to be a fighting game, and that means you need to fight. If you have no reason to expand, as in to protect yourself from the larger players, then why expand at all? Currently, you want to expand as fast as possible after your forces get wiped the first time, which would probably mean, if you were so far beneath the other player, that you would buy premium in an effort to catch up. Now why bother.
And you are right, you should keep major game changing mechanics to new servers. Otherwise, you just get people complaining about it, and massive quits. Sure, introduce small changes gradually changing the system, but then there is less likely to be complaints about it because we adapt as we play.