Outside of South Africa and England. Everyone else will probably be evenly matched. This will mostly be due, to each of the other sides having continual depth issues at certain aspects of the game.
The only team that will significant decline will be Sri Lanka, due to the fact they will be losing anyone that is half decent. I think AUS, PAK, IND, NZ & WI will be playing musical chairs with the middle rankings, and Zimbabwe and Bangladesh, will be continue their role as the stat-padder.