Working effects/lights on Duel have gotten far better over the years. The timing of effects and replacement of lights has made it worse. So really it's no better than it has been for a very long time. I'm no techie with lighting, although whatever they've been replacing in some scenes has made parts of the ride awful. You have new lights that light up entire rigs, ruining the jump scare effect (because you can see the rig swinging at you 3 seconds before the 'scare'). The screaming faces scene is entirely ruined, you can see all the rigs again, and also clearly see the walls and where the track is leading you (used to be invisible pretty much). Spider scene, ruined. Flying bats, ruined (because I can see the string and metal spinning above me).
They need someone with a brain cell to go over the ride and sort out the lighting. It used to be very cleverly done, no rigs in sight, the track almost invisible, so each turn was a shock in itself, props that seemingly come out of no where.
Duel has good foundations for a ghost ride, although what Towers may think have been improvements in recent years have just made it far far worse.