You know, before answering the other question, there's something I want to say here which I think is important . A game is not a feature list. I look at D:OS and I can't believe how much we put in there - it's 5X the game we originally planned and I'm very proud of what my team accomplished with the few resources we had. What I'm the proudest of however that each feature that's there has sense, and isn't just something for the back of the box.
Whenever it came to deciding where we'd put our effort, we always prioritised according to what we thought would be the best for the game experience. If an existing area needed an extra iteration to make it more fun, we preferred that than just adding a region for the sake of quantity or feature boxes. It's a lot easier to make large boring areas than fun ones. If it came the improving the quality or importance of certain features in the game(e.g. perception or charisma) we preferred that over adding new things. Obviously that means that resources are used in a more focussed manner, but I think it benefited the game experience tremendously.
Tha said, we planned on 4 companions - 2 more will be added once we've taken some fresh air. The AI personalities are going to pop up when they're done which I expect to be fairly soon. As for the dungeons, that's really a non issue. The size and especially density of the world and dungeons that are there largely compensate. This was supposed to be a 40 hour game, it easily is a 60 to 100 hour game.
