I think everyone is missing the point of why Disney is doing this. No one sees Captain EO. The theater is not packed and most times half empty. They are going to need a TON of capacity when Frozen opens up. The third theater will help a little, but they need more. Putting Pixar name on anything will bring in WAY more guests than Captain EO did. They don't have time to build a whole new ride in that area, so doing this will help them. I don't think anyone thinks this is permanent. This is to help them until they can redo this whole pavilion. I think they are doing this now to test it during Christmas crowds to see how popular or unpopular it will be and if they fill the theater like they want to.
Also, mot everyone uses netflix or has seen these shorts. So it would be new for those people. Also, it will have a slight spin on it for those that have seen it, since it will be in 4D. This is not something that they are looking for people to return to over and over. They just need to handle crowds in Epcot.
I think we will see a couple other small things done to Epcot to get it ready for Frozen opening.