Except there was nearly another way. In this interview for Doc Oho's Reviews, Simon Gurrier, who wrote the Second Doctor installment reveals the original plan was for Matt Smith himself to turn up in all of them playing the Eleventh Doctor and interacting with each of the readers playing the other incarnations and so forth, which is significant especially in this case because Fraser Hyne's Troughton impression is uncanny:
"As for the Eleventh Doctor, I don't think I'm breaking too many confidences when I say that the original plan was to have Matt Smith cameo in each story. As I remember, that didn't happen for boring logistical reasons – we needed to deliver the first two stories quite early to get them out in shops by January and February 2013 and the schedules didn't work. So my favourite bit of the script I wrote – the meeting of Frazer Hines' Second Doctor and Matt Smith's Eleventh – had to be massively reworked. These things happen, but when I hear the story now, I do miss that daft scene."The scene is included in the interview and it's really, really good, especially the bit about the obvious, because you'd have to mention that. Sigh. Missed opportunities agogo.