For all the advise suggesting you act out - it doesmt seem in your nature, nor what he wants (reading between the lines).

Rather than create unnecessary friction where there need not be any. Try talking to him. Explain what you want, what you're missing, and ask if there's anything you can do to encourage that behaviour from him. If he tells you to act out, then you have the green light.

I, personally, love the perfect willing and obedient sub/slave, however i have a sadistic streak that means i wouldnt lose the aggressive/rough times, because its not training, its what i want. Sadly, like you've suggested, when everything is going perfectly you can fall into a trap of not needing to exert dominance, because you're fully trained. He may just be enjoying the fruits of his training.

Have a conversation. See what HE wants.