Sometimes Maestro Inoue wants articulations short, sometimes long, sometimes we are too loud and sometimes we are too quite. He has a spontaneous imagination and it can be hard to predict what imagery is occurring to him at any given point. Bagpipes, tickling, robots? These are just a few of the suggestions he's offered. Luckily he is very expressive in his gestures.
It would likely be much easier to predict if I knew the opera much more than I do. I've watched it online with the supertitles and generally know what each aria is about and who sings it; but as to the specific words being sung and the intention behind them, I can't be sure. A loud passage might be joyful or angry, and it might not always be so easy to know which direction to go without knowing the words at a particular spot. There are so many ways to interpret instrumental music, such as a symphony, but once there are words attached to it, things get a little more directed.
And so Maestro Inoue has to help us. None of us, save perhaps the concertmaster, knows the opera as well as he does. He has to tell us what to do to support what is happening. Should this be a strong forte, or should it trail off? How sharp are these articulations, how noble, how angry, how sweet? We just don't know. It is as though he is telling us how to walk by instructing us to move each individual muscle. If we just knew the goal, it would be so much easier.
But we don't. And that's how opera works and to some extent the way that orchestral playing works. The conductor is there to know the big picture better than anyone else. That's the conductor's job, and our job is to do what they say. It seems there should be a better way, but then I think that's what chamber music is. With too many people, there are too many ideas and so we have to have a dictator and that dictator has to be a patient teacher. They have to have a strong idea about what the work is and should be and they must communicate that to us as fully as possible. And the more of the picture we can grasp, the better able we are to realize their ideas. We are the black box, receiving inputs and creating outputs. But with more knowledge, we can help in the generation.