I'm familiar with the "old" KC airport. It was very easy to get in and out of because it was so compact, but once airline security became a big thing, the size really held it back because the entrances to the airport were very close to the gates, like 50 feet away. So for the last 20-ish years, once you passed through TSA, you couldn't get back out to walk around or get a drink or bite to eat without having to go back through TSA after. Your other option was to just sit and wait by the gate the whole time, so if your flight ever got delayed or if you were with fussy kids, it was an absolutely miserable experience even by the standards of air travel. Eventually they put in a couple grab-and-go type kiosks and Starbucks but it was very lacking.
Thankfully, I've had pretty good luck there but the new terminal looks like a major upgrade.