First taxi light because when taxing at night a taxi light would look more realistic. Along with when taxing not having to use the landing light as a sub when taxing. Also lights that kind of shine or light up off of the aircraft. It would make it easier to taxi at night. Along with light up the runway infront of aircraft it would make take offs and landing so much cooler. Also adding a couple more lights like logo/tail light to eliminate the tails. It would be a great add to the 3D airports. Finally taxi way lights that would make easier to taxi at night.
I believe you’re referring to a more realistic, volumetric lighting that mimics the real world more than what it currently is. I’ve linked below a couple of feature posts where you can vote on them to show the developers what you wish to have added.