One of the biggest problems I've had with Portland's defense this year is how defenders position themselves when defending off the ball. They often get caught in between fully helping and staying out on shooters. They often do this even if the ball-handler isn't going downhill.
They need to stay attached a bit more until the ball goes downhill, and then either help all the way so that they could make the kickout pass tough and so that the other defenders know to rotate, or they need to stay more attached.