Re: Zazen necessary for training
I've done both zazen and aikido for over 20 years, and for hundreds of times have sat nose to nose and stared into the eyes of the 105 year old zen master Joshu Sasaki Roshi ... my 2 cents.
For any level of understanding you will eventually need to ... reconcile the past, reconcile the present, and reconcile the future.
By itself, sitting will help you reconcile both the past and the present.
By itself, aikido will only help you reconcile the present.
And only a true teacher can get you to reconcile all three.
To that end, I see zazen being somewhat of a plus to an aikidoka (in dealing with the present moment), but neither by themselves or the two together is capable of getting you to any true level of understanding.
For that you need a true teacher. Do you have one? Are you one?