Here's my 2 cents on the worst idea to come from the Once Writers' Room: Treating the Frozen arc of the first half of season 4 as a continuation/prequel to the film's events (sadly, that was actually when we began watching the series live. We were recording it when it first began because we were watching something else. The only time we saw it live was back when they were still doing the Winter Break instead of the Winter Hiatus). It really betrayed what they had said prior when the show was first getting off the ground: 'Our series will not affect any future plans Disney has for these characters and elements going foreward' was something the creators had used to explain how different Once would be from the main Disney formula and we got that in the first three seasons of the series. By the time season 4 rolled out, they had a little bit more clout and used it to clear Frozen (2013) way before the film even hit the store shelves and said questionable statements that really confused the members of the Wiki (in one interview, Adam Horowitz stated they 'were not redoing the movie, but the movie's elements and characters would remain intact', contrast this to what he said about 'The Princess and the Frog': 'We're not redoing the movie, but we have a spin on the movie's elements and characters planned that we think the viewers would enjoy') that led people to think the crossover would be considered canon in terms of the overall franchise since it would be the first franchise related thing to come out of Frozen (the short wouldn't happen until 2015, although it would have been in pre-production), even though Eddy Kitsis stated that won't be the case (ie: 'Nothing we do on the show is canon into the Frozen franchise', which was later revealed to mean, on this Wiki no less, that they meant in terms of the greater franchise, the arc isn't canon, but the events of THE ORIGINAL MOVIE would be treated as canon. Another factor to consider is that Kitsis also gave an explanation before that Variety interview, in an interview with Science Fiction that basically amounted to 'No one at Disney or ABC cocked guns to our heads and said 'We want you two and your writers to map out a story arc for Frozen', claiming how it always worked is that they always pitched Disney with their ideas and reinterpretations). The arc also had the weakness of Disney being a bit more hands-on with them as well, which, I think, really hampered how far they could twist the characters and elements (I WILL concede that Canon Welding The Snow Queen into Frozen was clever, to the point that I did the same thing with a story I'm working on, albiet slightly different). I say this because in their season 3 postmortem, when asked if Disney will have substainial imput into how Elsa would be protrayed on the series or if they have a blank check to write her however they pleased, giving some idea what goes on BTS, Horowitz stated 'The process, we're guessing, it will be similar to how it's been with all these characters. In many ways, it's like using Snow White, using a character from Frozen-It's just a 100-year difference. Our scripts and our ideas get vetted by the STUDIO (ABC Studios) and the network (ABC) and DISNEY'S BRAND MANAGEMENT PEOPLE, and we're sure that process will continue' (it shows that Disney DOES have some degree of imput and say on what can and can't be used and featured on the show). Frozen producer Peter Del Vecho also gave an interview in August where he stated he went to the Once Upon a Time writers' room and gave them notes about how to protrary the Frozen characters (although he didn't say whether or not he was familiar with the series or if he was asked to supervise by Disney or if Chris Buck and Jennifer Lee were there with him at the same time or at different times during the writing phase). Brave was guilty of this too, but I can give Brave a pass because they found a way to integrate Brave into the overall arc they were trying to build in the first half of season 5, whereas with season 4, there was no real attempt to integrate the Frozen characters into the overall arc and to be honest, they really spent most of it going 'Hey, remember this from the movie?' almost like it was trying to shove down our throats that it was treating itself like a continuation and there wasn't really any attempt to build an arc around it like Neverland (you got the semblance that there WAS an ongoing arc forming, but it was mostly forgotten until 411/412, season 4's Winter finale. Slash represents Broadcast/Streaming) and the ultimate storyline of 4 had no real place for the Frozen characters to romp around in, whereas with Brave, we got 'the film's events happened, moving into the overall season arc now'. 4A just felt too much like filler to me, honestly, as well as the fact they were trying so hard to tie it back to the movie that it resulted in a very 'off-like' feel that didn't really mesh with Once's visual style as well as more overt 'winking to the camera' moments (ie: Regina secluding herself, the gloves, Emma's hair, as well as the obligatory 'Let It Go' reference (building the staircase and then running across it in the EXACT SAME POSTURE) and the 'And I sang with you!' line referencing 'Love Is an Open Door'). Those moments I listed in the parenthesis are where I kept waiting for the actresses to literally throw winks at the camera (bare in mind, Once 'winked at the camera' a couple times with their nods, but they were more subtle winks, like having Gaston in Belle's story) because those nods were so overt. In the end, the arc wasn't HORRIBLE per se, but the writers, Kitsis and Horowitz included, did make choices that I personally didn't really agree with and if it was more thoroughly integrated instead of trying to 'half-heartedly forge' a connection (like Oz was foreshadowed, Agrabah was glimpsed in the spin-off), maybe I would have enjoyed it a little more.