As planners, I'm sure at least some of us have had crazy ideas about counties that are too small, too large and should be divided or consolidated as such. This can also include cities you think should be consolidated with counties as one unit, or vice-versa.
For one, I think Cook County, IL is too large for its own good. At more than 5 million people, it stands as the 2nd largest county in the U.S. DuPage County was carved out of Cook ages ago by people wishing to preserve their rural and conservative way of life and escape the corruption and crime of Chicago. Additionally, McHenry and Lake used to be consolidated as one. If not for the division, this county would currently contain 1 million+ people and governing from the lakeshore to the prairie would be quite difficult indeed.
But still, Cook is way too large. There are still plans on the drawing board to create new counties out of the northwest suburbs in Cook (Des Plaines, Schaumburg, Arlington Hts., etc.), as well as the south and southwest suburbs (Calumet City, Oak Lawn, Tinley Park). Both areas want to become called Lincoln County. One would be moderate, leaning conservative, the other would likely still be Democrat. Nevertheless, the local needs of these areas would be able to be more adequately addressed.
I think they should go for it. Smaller, more local government, IMO is better. 5 million people just cannot be governed effectively by one body.
Also, what about L.A. County (9-10 mil. ), Harris County, King County, and others? Do you agree with the Borough system in New York?
On the contrary, what about Atlanta and Georgia as a whole?? It can also be difficult to manage and comprehend a major metropolitan area that has dozens and dozens of random counties and reckless sprawl, as each county tries to compete for tax dollars.