I don't see anything excessive at all in the points your shihan stresses. The only thing I would have a problem with is the seiza, as my knees often just don't allow me to do seiza for very long.
It was maybe a bit misleading to give those examples of etiquette in detail, because of course it's not just about that. In the same way it's also about expecting from myself that I do what is shown, and not ignoring little seemingly irrelevant details in technique, for example. Our shihans dojo has members who can't sit seiza at all, some bow in standing. It's not really about the details.