Great points XPin.
It's been my point all the way, that the LCD on the JJP platform does not suit the pinball machine well. It's too dominating to the playfield/lights. Like serving fine wine at KFC
But it will have an appeal on operated games to attract players, educate game objectives and run advertisement. Which hopefully will make games in the wild more attractive for locations and operators.
PCB's with surface mounted LED's, run by a serial bus carring both power and signal, is the way to go. There will be developement cost and perhaps higher cost of manifactoring parts (though the traditional wiring harness looks labour intensive). But, ease of assembly and maintainance. The benefit of LED's, like em or not, is obvious for an operated game powered on for 100's of hours a week.
Don't know if it will work for solenoids. But you could still simplify wiring by having more smaller and decentralised driver boards mounted underside the playfield. Boards are controlled in serial from from the CPU in the backbox and having power directly from the PSU in cabinet.
Oh wait, why not have all boards in the cabinet. Could simplify and cost reduce the backbox.
And while we're at it. Imagine a bi-directional bus also going to PCB's with proximity switches rather then micro switches.
I believe Marsaplay are there already. However that game seems a lot simpler.