When we talk about music, we talk about our reaction to it. One person might say that music is so poetic, while another says it's all mathematics. Yet another might say it's about sensuality, and so on. That's all true. But music is not just one of these things. It's everything all at once.
Most of the dramatism in Wagner comes from a very close link between the music and the language of the text. So much of the expressivity of Wagner's music dramas comes from the singers' capacity to play with the sound of the language. This kind of thing you can do very well in concert performance.