...the convoluted ret-coning of "These Are The Voyages" (why 2155 instead of 2161?)
Because TATV doesn't really make sense as a story set in 2161. The script, so I gather, was originally written to take place in 2155 but got hastily rewritten for a 2161 setting when the show was cancelled. And that introduced a number of anomalies. Why has nobody advanced in rank or position in six years? Why has Trip and T'Pol's relationship been in stasis for the same duration? Why is there no mention of the Earth-Romulan War? Why does Deanna say that the alliance established here is just the first step toward the Federation, rather than the actual formation of the Federation itself? The account as presented in the episode doesn't really hold together. It's a better fit to 2155 than it is to the alleged 2161 date. So The Good That Men Do
explained those discrepancies by positing that the historical account, like the teleplay, had been adjusted to look like it happened in 2161 rather than the original setting of 2155.