I dont really consider the economy of running a high spy country, because it isnt financially sustainable to do so....period. You can get to maybe 20 or 30m but at some point you're going negative $ no matter how much production you have to offset it. The game punishes you for having high spies on many acres.

I like the idea of total spies mattering more, truly I do. But it's hard to think anything encourages more spy building on better countries when it isnt financially sustainable to run any more than we already do.

I think maybe creating a country on alpha with 30m spies and attempting to run some turns at various acreages and war builds/MUs might be wise. You'll see that reaching that maximum isnt viable, and that the value of running a higher spy total will not change.

Currently on a 40m troops country, 10 CDs would kill about 12m troops. On a 20m spy country, it could kill....8m?

I think that is totally fine and decent. The very top end of economy for spies will kill about 3/4 of what CDs do now. It will make killing as restarts way more difficult, and will encourage better building.

The one thing it will not encourage or add economy to, however, and be absolutely sure of it, is running higher spy totals.

With that in mind, I worry wars would become endless with kills getting more and more difficult as the war progresses. And I absolutely wholeheartedly disagree that the war meta needs to be any lengthier. The only thing that sucks worse for activity than having 6 straight weeks of war is having 6 straight weeks of war and no clear winner.