I just went from a Crown Vic with auto lights to my Expy with just a regular light switch. I knew I was going to miss them and I was right. They came on when you opened the door to start her up, I never had to worry about turning lights on or off and mine had a timer that you could adjust the duration they stayed on after you switched off the car.
This was a good feature for me as I could point the car to my door to light up my (otherwise dark) walk to my front door. But it's all about adjustment.
To add that feature you'd need a light sensor that goes in the dash and think about all the wiring involved with that, too. Wouldn't be worth it to me no matter how much I miss it.