Voltopt, the new central terminal is a great idea. Get to work on it immediately.
I would enhance your design in the following ways.
I'd connect all three terminals with skywalks behind the security checkpoint so people can move about all three terminals without having to go through security each time. This is so some passengers can switch planes to another airline if that is how they are traveling. For example, Continental from Chicago to Kansas City, then Midwest Airlines to Columbia.
I'd add a Terminal D so more gates would be available for the future. However, with Terminal D, I'd use the terminal core as a meditation garden. People with long waits between flights might enjoy it. Of course, there would be one of Kansas City's famous fountains. It would also give smokers a nice place to hang-out without violating indoor smoking bans.
I would advocate that the new central terminal be a glass dome, so that natural light could come into the terminal. Then one could design the terminal space to be like a botanical garden of sorts with sculpture and art. This would be a very calming environment for stressed-out travelers. It would also make our airport distinctive and pleasant. Throw in a couple of giant fish aquariums as well to give people something to look at. In addition, having amenities like gym, showers, spa, massage therapists, and chiropractors onsite would be great.
I've added a light rail hub to your design that connects with the central terminal in a turnaround design. The rail hub is connected directly to the terminal so passengers don't have to go out into inclement weather to transfer. It would also be great for airport employees to use to get to work. Under some situations, some passengers stuck in ice and winters storms could take light rail to Union Station and then take Amtrak elsewhere. That way, if people are stuck for days like in Denver, they have easy connections to other modes of travel.
Anticipating the comfort needs of stranded travelers who end up sleeping in the terminals, I've added two hotels that are connected by skywalks. This will give passengers who are stranded a place to spend the night in comfort without having to go to a lot of trouble riding shuttle buses, or taxis. The hotels are in short walking distance, and thus aren't dependent on shuttle bus schedules, and time worries. The access also allows them to leave the hotel and frequent the terminal at the variety of restaurants and shops.
It also anticipates the occasions when one has already checked their bags, and don't want to have to go through security again. This way, if their non-carry-on luggages is already placed in bag check, they don't have to deal with that. They can just walk to the hotel, sleep, and come back without a lot of trouble.
This will also make it easier to make a plane should the flight be delayed for just several hours. Under this scenario, the passenger can check into a hotel room, sleep for a few hours, and have the airline call them in their room if plane is placed back on the schedule. Then, once they are called, they can just walk over to the terminal, walk through the metal scanner, and get on the plane.
The other nice thing is with a light rail connection, if they have several hours of delay, they could take a ride into the city for amusement.
I recall one time being delayed for six hours in at the Pittsburgh airport. Something happened when the systems alarm went off during our taxi on the tarmac, so we had to deboard the plane and wait for another to be flown in from some other city, get restocked, refueled, etc. I was bored out of my mind, and very tired. It was a suck-ass airport too. It seems much worse than KCI.
I would have killed to have an on-site hotel to crash for five hours or so and sleep, watch TV in privacy, and take a shower. Having amusements like a meditation garden or fish aquariums to look at would have reduced my stress-level as well. I've also thought it would be great if airports had small in-house libraries for people to spend their time waiting during delays. You could look at coffee table books on photography, architecture, gardening, history, etc., while you waited. Ours could be stocked with all the books on Kansas City, and area attractions. I'm sure that airport employees would enjoy it as well on their lunch-hours.
Had Pittsburgh had a light-rail connection, I could have at least taken a ride into downtown Pittsburgh and looked around for a couple of hours. I've heard that people with hours to spare between flights in Atlanta take MARTA into the city.