I don't get the shock and surprise that they might think to add this to Epcot. The EPCOT of old has been dead for years! Future World is a graveyard. World Showcase is a way to sell Duffy Bears, princesses, and Perry the Platypus. The original mission statement of EPCOT has been dead for so long most visitors don't remember what the place used to be like.
At this point, I'll take anything that is a GOOD addition to the park. If a Frozen overlay is done well, it'll fit with the current state of WS (in which anything even tangentially related to the country is hamfisted in). If it's not given proper budget and thought, well, it'll fit right in with other "wonderful" rides like Imagination, Nemo, Ellen, and pretty much everything else there.
Every time it hear the soundtrack (and I have young girls, I hear it quite often these days), I just keep thinking how this show was made for Broadway. They want more Frozen in the parks? Replace the Beauty and the Beast stage show at DHS.