Which existing feature did they remove? You could still use Google maps (and you still can).
https://techcrunch.com/2012/09/26/the-apple-ios-6-maps-fiasc...
IIRC, one of the big reasons it was an upsetting change is there wasn't an option to change default apps and google didn't even have a maps app when iOS6 dropped, so if someone sent you an address, or you clicked on an address link, it always would open in the apple version. Which at the time was dogshit terrible, it was like stepping back in time 5 years.