I don't have a problem with Frakes/Riker or Sirtis/Troi. Bad Thoughts' Trials suggestion could possibly work, if Riker and Troi had been visitors from the future, perhaps even there to ensure that NX's mission would succeed. Though that scenario then has an echo of Star Trek: First Contact and everyone would criticize that being reused instead. Bringing the pair in as essential to helping the crew complete a mission would be preferable to what we got. But watching it as a replay just didn't work for me, because it made Riker's personal crisis a major element of the story, which should have instead been about Archer, T'Pol, et al. And if a viewer had been unfamiliar with TNG, they would have had no idea who those two people were or their significance.