I really agree.
I think that if this project was to go ahead, it should be a campaign to create more little pieces of theming; to urge the art department to take another look at every ride and make plans on how to improve them. Whether the art department already does this I don't know, but it would be really nice to see more of them.
For example, the skeleton bed effect from the Haunted House was recently rewired and now lits up again. That meant somebody made the effort to add/fix lighting and programme it to trigger when the car came past, etc. However, nobody has yet gone far enough to actually 'restore' the effect, as it does not move and has some dodgy attempt to hide the fact that the skeleton has no skull.
Why not fix the effect completely? Make a new one perhaps? Add brand new effects throughout the ride? Even redecorate/retheme certain scenes so that it makes sense again, if you want to go that far...
Perhaps Nemesis could have some lighting/sound installed that trigger on every dispatch?
Maybe evern Thirteen could have new details here and there, such as a body in a tree in the near distance?
They did this type of thing a few years ago with Charlie and the Chocolate Factory, and they used to do it all the time with the Haunted House back when it was new. It will still work now - small new touches that make a difference.
The problem is, this could just be seen as a waste of money because "only a minority of guests will notice the changes". There are many reasons as to why I disagree with this, but it could still be enough to put people of investment and keeping the rides as they are.