TWD has a slew of other issues besides code that make it a bad design. Lets not pretend that TWD and Kiss have much to do with pinball. It's more about the theme and eye-candy on both of those machines. They get played a LOT by non pinball people on location. That does NOT mean that they are well designed pinball games.
I know those that love the two games but that seems to be the exception, and not the rule. There is simply no comparison to SM, LOTR, MET, etc. if we are spouting off about other Stern titles.
TWD and KISS are certainly "behind" the fun factor of those games and "new code" is not fixing that.
Another case in point: Stern Star Trek. I don't know Star Trek, I don't care about Star Trek, but that game is a very well designed table. So much better in so many ways than TWD or KISS, if we are being honest. I like Kiss music and TWD is a fantastic TV show but that really has nothing to do with how well a pinball machine is designed. Theme implementation can only offer the pinball player so much. It can add a lot to the entire pinball experience, but it should never be the starting point to find a great playing pinball machine.
Pinball is different things to different people that play the game. Theses are all just opinions. Those that like KISS or TWD certainly see something in those games that I just I don't feel rewarded about as a player or buyer.