Unless Miller is adamant about wanting to leave the Canucks, then I don't see how we can trade him this year. I'm thinking that trading him at this year's trade deadline, with the team playing so well after getting rid of Green, would be a big gut-punch to the rest of the team by sending their best player packing. It's essentially a message from management saying that they don't believe in the team despite their high level of play this year, and I'm worried about the effect on morale.
If the Canucks don't go anywhere this year, and seem to be out of contention next year, then trade him at next year's deadline. If we get less assets in return, compared to what we would get this year, then so be it.