What's needed are Tri-State access ramps for Franklin Park and Elk Grove, not a by-pass just for a western O'Hare terminal.
A Tri-State by-pass of O'Hare with an Elgin-O'Hare connection would short-circuit the Northwest Tollway.
This seems planned in a vacuum - another thing that's needed are Metra connections to the West, Northwest, and North Suburbs and Amtrak routes over conventional and high Speed Midwest corridors are needed as well; but many issues an alternatives need to be evaluated.