It is possible for there to be some middle ground you know Some irrevocable damage to an are of the Old World that doesn't quite amount to 'Empire flattened' would be ok. Killing off characters is fine by me- it makes sense that war like hero's aren't going to survive every single battle they take part in.
The original idea was 4 great forces crushing the rest of the world, actually leading to the final victory of Chaos. That was the plan, no middle ground. Rick wanted it to end as the big end.