I remember a town hall about the single terminal proposal that happened at the central library like 2-3 years ago. My two take ways from that were:
1) The Q&A and panel quickly dissolved into listening to the imaginations of quite an eclectic group of insane people
2) Pretty much everyone there, insane or not were firmly, and I mean firmly, against making it be a single terminal
Granted that was about 400 people or so, but I literally heard 0 positive reception to a new terminal, and those who had even anything positive to say about it were simply not as adamant as those against it.
I went into that meeting just out of straight curiosity and with some coworkers, and not a strong opinion one way or another. Now that time has passed, there would be a lot better things for KC to spend $1 billion on, and as long as things stay as convenient as they are for the vast majority of serious business travelers, it ain't changing. Any small fixes, including just freaking adding precheck to American can be achieved w/o throwing out the entire airport.
Also, apparently Panj and I have the exact same travel habits in how we use MCI.