I think they all have their merits, but there’s a difference between being flexible with the motions and doing something completely brand new in performance that might freak out the players. I know that even in performances, I’m not just buried in my music or what the others in the group are doing. There’s something to be said for spontaneity, but “Surprise, I just decided to change the entire feel of this section!” may be a little drastic.

And about always using gestures, it makes sense to gesticulate while talking. I do it all the time without thinking about it. But I don’t know if it’s a necessity, especially in a professional or pre-professional atmosphere.

-Ben