I used Pacifist to install Airport Utility 5.6 when I upgraded to Mountain Lion. So I didn't really notice how many features Apple removed with the Mountain Lion/Airport Utility 6 upgrade.
Recently though, I wearied of having to restart my (only) 3 yo Time Capsule every 4-6 days to reenable Time Machine backups. I ordered a new TC from Amazon to do a hardware swap test (30 day return) and, for no good reason, I tried using Airport Utility 6.2 to configure things.
It was an abysmal failure. To start with, it failed with a meaningless error message when it tried to join my existing network. For another I couldn't archive my Time Capsule backup -- and I couldn't disconnect guests and backups prior to power down. A Jan 2012 CNET article has the long list of lost features -- not to mention support for older devices.
In retrospect, Airport Utility 6 was a big initial step in a trek that included the iOS podcast.app and iTunes regressions (though some functionality was restored to iTunes). January 2012 was the start of what has been a long and disappointing 15 months for customers like me.
WWDC 2013 will tell us if Apple is going to change direction.
I hope the rumored Microsoft shakeup is a very big one. I have a bad feeling I'm going to need them.