1) Sideblade art is a start I would do the Chocolate river with the boat on one side, and the forest of treats on the other.
2) It needs the elevator much like Houdini mod with the water chamber
3) Not a fan of the metal box to the left of the gobstopper. I think what would be better is a sticker that goes over the plastic ramp, then a boat to slip over that metal box. Create the scene of the chocolate river.
4) A mod to cover the area that holds the locked balls... I can think of many cool things that would involve adding a video like for example a video of bubbles and Charlie and his Grandpa floating, then have a mod that is a fan over the top of it. Maybe a balcony with Willy Wonka waving, or maybe even just a bubble in general that cover all that up.
5) I'm not a fan of the plastic rails, I think there needs to be a decal to make them look like lollipops like the stripes of a lollipop.
6) If you were to add characters maybe a golden goose, the girl as a blueberry, or props like suckers, etc from the movie that you just put up and around