Should the Temporal War in Enterprise have been used for crossovers?
I mean ... they had established actors, costumes, and sets in storage.
No reason they could not have had Chekov or Uhura in a time travel story, or Riker or Tuvok or Seven of Nine or Bashir and Dax.
What was the point of having a war across time without actually doing it in a way that integrated more of Star Trek?