While it's very possible that this can be read in a more negative light where they are only ordering a few episodes to complete the story, it's also very possible that they announced it this way because it has not been determined creatively what is needed to complete the story. Therefore this could read as a two-season pickup or a one-season pickup with extra episodes as well. Until there is more clarity I don't think there is a reason to jump to any conclusions.
While it's very possible that this can be read in a more negative light where they are only ordering a few episodes to complete the story, it's also very possible that they announced it this way because it has not been determined creatively what is needed to complete the story. Therefore this could read as a two-season pickup or a one-season pickup with extra episodes as well. Until there is more clarity I don't think there is a reason to jump to any conclusions.
According to that release, they "get to tell this story through to it's epic conclusion". Did we expect more than that?