I agree with ya; it seems like an impulse move to me.
I made the joke in my previous post with the thought(s) in my head on the cost savings in not having to redress or build anything. The guest loads, sits, the boat doesn't move, and then the CMs ask guests to gather their personal belongings, take your children by the hands and exit to the left... and some would probably wait a long time and love it.
To me at quick thought, any Frozen ride would have to include a sled set-up of some sort. It seems to me that some sort of show attraction utilizing tech could be a good route. I think of what was done with the mirror in Tales with Enchanted Belle (or is that Enchanted Tales with Belle??) and wonder if some awesome effects could be done with the room being frozen around guests and then so forth....
Ride or show attraction, I say please give Frozen the budget and space it deserves (not WS in Epcot IMO), do it proper justice, wow us and it will pay in return for years and years.
ETA: IF done. Also, Stars Wars and more Pixar in Pixar PLACE in DHS please.