I said it gave Vietnam an "edge", not that it discredited Indonesia's inclusion. Between Portugal, Venice, and Morocco we'd have three trade civs introduced in the expansion. We know that Firaxis has stated that they wanted to put in civs that display the new mechanics and so far there is nothing that directly relates to ideologies, which Vietnam could. I don't guarantee it but I'm fairly confident in this theory.
I also think Vietnam is more likely than Indonesia, I'm saying that Portugal as a naval trade civilization is filling Venice's role as well, since the developers have characterized Portugal as the expansion's quintessential naval trade civilization. No guarantees yet about Morocco, but if they're focused on land trade that's different. Venice, however, is largely defined by its maritime trade empire.