Gleason Sensei always stresses that training with bokken is an integral part of Aikido training.
One point he makes quite often, still I am not able to get it through my thick head, is that one should not think of swinging the arms to move bokken, but rather all bokken movement begins in one's center. And is this not also true of all Aikido movements? (Just my opinion).
When I watch Gleason Sensei move with bokken, it appears to me that the bokken is part of his body. Each move is so fluid and smooth. And those are only the moves I can comprehend.
What I cannot see(strictly through my own blindness) is how each move he makes starts with his center.
IMHO, I think bokken training is a most valuable tool if one wishes to have their empty hand techniques begin from their hara..