well done on the repair

It would be a better option to overhaul / rebuild the driver board than to replace it.
But if it is working fine then leave it as it is.

I would never put a board with surface mount devices in any of my machines.

I think it's time for a Home pin, Stern / Bally driver board to come into existence. 

Yes, it is on the list. One thing is for certain, it will be made with COMMON, easy to find, through hole parts.

I will get rid of the CA3081 transistor arrays the same way we have done with the Zac MPU and I am still pondering the 5V regulator BUT I refuse to go switched mode like some other after market board makers - it just doesn't cut it for these machines in my experience.