We spent the day at Agri trade in Red Deer, a massive farm equipment exposition.  I haven't paid much attention to new combines in recent years, but I peaked in the back end of a bunch of different colors today, and saw a common theme, while capacities and class have grown incredibly, sieve area hasn't.  I just checked the specs to see if it is my imagination, and it isn't.  I run a 20r old MF 8460, with nearly 8000 sq inches of cleaning area, yet the 9120,CX 8090, and CR9090/970 have only 10000,   a 7088, 9870, 9895 all have about the same as the 8460, S77 has less, Yet supposedly much more capacity.  
What is the secret that allows them to clean so much more grain over the same area?  Are rotaries really that superior in not overloading the sieves, that seems hard to believe considering what they do to the straw?  I can't see any other radical innovations to the cleaning system that would make them more efficient, still looks the same as the average threshing machine.

A quick way to compare the specs:
http://www.caseih.com/en_us/Pages/compare_specs_results.aspx?idProduct=52&mn1=Axial-Flow%205088

Please enlighten me.   I highly doubt that purchasers of new combines are settling for double digit losses, so it must work.