Aside from the thematic fit of Cars in Frontierland, I worry most about the loss of the geographic diversity in the park. ROA provides the park an medium other than cement. The water provides a visual and emotional break from the chaos of the sidewalks. Even though it is a man made waterway, it’s still a waterway, and people find waterways peaceful and relaxing to be around. MK used to have two major water feature focal points - ROA and the submarine lagoon. We lost the lagoon, and now we’re going to lose ROA, leaving the MK with no water feature focal points.
My biggest complaint about Tokyo Disneyland Park is the lack of geographic diversity - the park feels like it is a bunch of building sitting on a flat parking lot. Their ROA is tucked in the back, so it provides little to break up the park’s walkway monotony. For example, their HM is kinda just awkwardly stuck off a big flat walkway. Compared to the HM in WDW, DL, and Phantom Manor in Paris, which all have the ROA, the TDL HM never had the majesty and beauty sitting on a hill next to the river and that hurts the park. It is something the got 100% right in the mix of geographic diversity at Tokyo DisneySea. It feels like WDW is intentionally going the rout that TDL inadvertently took 40 years ago.
EPCOT has the world showcase lagoon. DHS has the lake. DAK has the river and lagoon. DL has their ROA and their submarine lagoon. DCA has their lake and their water ride. DLP has their ROA. WDSP has their lake. TDS has the Mediterranean lagoon and water all over. Big water like that at a Disney park is not at all a waste of space. The water is soothing and relaxing and helps everyone have a moment of calm. No big water at MK, the busiest and most hectic theme park in the world, is going to hurt, regardless of how good the Cars attraction may be.