Deep chaining is currently the only really feasible way to disable a province. The reason that deep chaining is so used is because it's simply too dificult to kill off offence.
If it was made easier to kill off the offence of attackers then the need to chain as deeply would decrease or go away. So either change overpopulation mechanics to include troops out on attack or come up with some other way to touch troops out on attack that doesn't depend on ambushes.
I do think that the game needs to have some destructive elements. I don't want a game where every war is an endless slugfest where there is no noticeable change until the game decides for you by some completely arbitrary metric that you have won/lost the wars. Wars should have clear winners and loosers where both sides clearly sense who has won/lost. That being said, recovering troops is a whole lot easier than recovering acres and troops so if we could decrease the need for deep chaining by enabling proper disabling of provinces at larger sizes that would be good.