C Tickets should be zippy. There’s usually some nice, interesting stuff to look at in a C ticket, but there’s not enough room in the budget for everything to be nice and interesting, so the ride needs to move you through them quickly so you don’t realize just how many blank walls there are after that cool bouncing with Tigger scene.
Alice, Snow White, Pan, Winnie the Pooh, and even Frozen (for the most part, at least) are zippy. Mermaid and River Journey are not zippy. Of course, they have their own problems, but when you don’t have a lot of nice (Mermaid) or interesting (NRJ) things in your ride, making your guests look at them for longer doesn’t help.