Quoted from flynnibus:PROC is first and foremost hardware interface and set of drivers... they can run the same game code and just change the hardware drivers and interface in the software. They could run on the same PCs you already run alien on even.
One could in theory just focus on changing the IO boards and keeping the existing lighting/switches.
It's not as insurmountable as you infer. It's more a question of how much you think should be salvaged. That drives the scope. Swapping out the IO boards and keeping the same mech/switch/light junctions could make for a very 'swappable' upgrade. But if you want to ditch the power design, light boards, switches, etc.. then things obviously get more involved. But those are kinds of things you can do readily for a game going into production.
I didn't say its insourmountable. I implied it isn't feasible from a cost perspective.
It can run the same game code? Sure, if there is an interface layer between the two. I'm a software engineer, and no, there is no just hooking up a p-roc board to the existing computer and it magically working.
Removing the io boards and expecting p-roc to interface with the existing lighting/switches is a bit far fetched. The only thing you have done is gotten away from the problematic usb connection. You still have a number of failure points like the terrible switches.
This of course ignores that there isn't enough incentive to redesign this game which was why I said it wasn't feasible in the first place. You need a company that has the funds to buy out pinball brothers, buy the license from fox, have the facilities or the funds to build them, and the funds to redesign the game and put all the parts back in production.
To date with remakes we have seen BBB which sunk Gene Cunningham and required multiple people to bail out the limited production, using a lot of pre-existing parts. We have seen Chicago Coin which has remade games where a lot of it was already existing and overtime they have introduced changes. So, no let's put this stupid question to bed because after over a year of idiotic, unfounded, bullshit rumors we still haven't seen this game remade in any form let it go.