Disney's biggest issue is they don't trust their IP's enough and wait it out to see how a movie is going to do. In order to rush something out, they created this by shoving it into a already popular ride. I'm am surprised and impressed with what they pulled off but it really falls flat at the end. They knew they were making a Frozen 2 for a while now. They should have waited and designed a ride from the ground up to open right around the same time as Frozen 2. Sure nobody was expecting Frozen to take off like it did, but they still waited around for quite some time before they announced the ride.
As far as what else they can add to Epcot, I would LOVE for them to add the Ratatouille ride to France! It fits the location perfectly and is far enough away from Norway to draw crowds over. Disney has created three amazing trackless rides overseas but they don't seem to want to bring them over to the States. If Frozen continues to draw the crowds, they are going to need something and building an already designed ride is a lot easier and faster than starting from scratch.