I see a lot of dramatic, expressive body movement in live flute performances, and I think it's great that the musicians are getting so into the music that it moves their whole body.
Interpretive body movements should never interfere with the actual sound of the piece. If your audience were to close their eyes, would they hear that crescendo, or would they just have to infer that it's there based on your floor-to-ceiling flute flourish?
What it comes down to is this; the audio version of the performance should fulfill everything the audience expects. It should hook them, keep them engaged, and execute the piece stylistically. Any body movement should be there only to keep you released and relaxed (for example, slightly bending and releasing the knees to prevent them from locking).
Engaging the audience and inviting them into your experience isn't so much about swooping around the stage. It's as simple as lowering your stand height so they can see your face, staying up and out of the stand, and looking out into the audience as much as possible. If you do these things, your recital attendees will feel like they're part of what's happening.