I would prefer to see the Portuguese as
Portuguese History - the Portuguese had Commercial interposts in every country; in his max, the Portuguese Colonial Territories covered a mass of land uncomparably larger than the original Portuguese Territory.
Religion was not a diving force of the Portuguese History: Other than Fatima (and that is only in the XXth century), Portugal hasn't any important Religous focus point. Although it seems, in latest inquiries, that the Portuguese are one of the most religious people of Europe, in actuality, the Portuguese History was much more built on the Expansion effort up until the end of the Portuguese Golden Age in the mid-XVII century.
UU - the Nau is much more coherent with a Expansionist Civ (if not a Maritime civ).
Gameplay: If the Portuguese become a Religious Civ in the Expansion Pack, those who play it have an incentive to build Wonders like the Hanging Gardens and the sorts. If they are Expansionists, the incentive will be to build those Wonders that are more related to our History (like Magellan's Expedition). If would make the simulation component of the game a bit more realistic.