There was always a risk that The Day of the Doctor, a special episode celebrating a 50 year old sci-fi show with an inordinately complex history, would devolve into nostalgic navel-gazing. But writer Steven Moffat managed to avoid it becoming too self-referential whilst still working in enough elements of the shows past to keep hardcore Whovians happy. However, Moffat seemed to miss a number of prime spots for a craftily-inserted reference that wouldnt have distracted from the main story and may even have enhanced the mythos. They wouldnt have required much extra effort behind-the-scenes, nor would they have disrupted continuity. Heres what I think was missed...
5. Not Using The Shape-Shifting Zygons To Sneak In Some Cameos
What was top of every Doctor Who fanboy/girls wishlist for the anniversary special? Thats right gratuitous cameos! When I heard that the Zygons would be making a substantial appearance in the episode, despite their relative obscurity in Classic Who-lore, I assumed this would be used as a way to work in cameos from past characters without having to think of a reason to bring them into events. Though I agree with Moffat when he says that the episode cant sacrifice screen-time to guest appearances just for their own sake, the Zygons could have enabled a few fleeting cameos without affecting the plot or the pacing at all. Whilst it may smack a little of Dimensions in Time to see the Doctor being chased across a field by John Barrowman one minute and Frazer Hines the next, there was one scene that could have easily accommodated a 30 second interlude for a series of quick-fire cameos. Facing the Doctor(s) and UNIT in the Black Archive, surrounded by photos of Who alumni, surely those sneaky Zygons would want to confuse their opponents by taking on the appearances of individuals known to be allies of the Doctor.