I'm not sure why there's such a widespread expectation that the Portuguese UA will have anything to do with trade routes. Certainly they were prompted to explore by the need to identify a new trade route to the east, but first and foremost the Portuguese are seen as explorers and navigators. They might have a shot at a trade UA in isolation, but probably not in a game where there are better candidates (including the Dutch and quite possibly the Indonesians), and above all not in an expansion in which exploration is one of the focal themes. It would be absolutely nonsensical to have an expansion with an exploration theme, include Portugal in that expansion, and give Portugal a UA that's about something other than exploration.
