It's perfectly salvageable and is no different than many of the other used WPC driver boards out there.
The previous tech working on the board didn't clean up after themselves. That can be cleaned up with a toothbrush and some 91% isopropryl alcohol that you can buy at any drugstore or department store.
If it's above the level of what you're weilling to tackle on your own, I've done mail-in board repair for numerous individuals on pinside, and can make it work perfectly for you. Send me a PM for more information, turnaround is a week or less and it's quite affordable when compared to what a replacement board will cost. My process doesn't just fix what you report is wrong, it fully checks out the entire board.
If you're the DIY type, there are plenty of techs on pinside, myself included, who can walk you through the repairs - but if you can't solder, or have never soldered, go find an old junk alarm clock to practice soldering on, before you jump headfirst into an expensive pinball board. It looks easy, but it takes practice and finesse.