I agree with almost all of this, & yes, retreats can be life-changing. They certainly have been for me!

However, I do not understand this comment:

For the Soto Zen and Vipassana traditions, practice is everything - not philosophy, opinion, or behavior.

Right action is an essential element of the Noble Eightfold Path. I have myself found the teachings concerning behavior to be a central element of my practice as I have gone deeper with the dhamma.