I'd say it's more like making a high-Essence Alchemical martial art that requires you to be a giant city.
Knacks are the physical attributes that govern Lunar shapeshifting and if the Lunar hero style does not integrate shapeshifting I can hardly see how it is a complete instinctive combat style for a Lunar. Shapeshifting is, physically, _the_ unique Lunar ability, and its' combat applications are myriad and obvious. It's no more their fault that other people can't shapeshift than it is a Patropolis' fault that nobody else is a giant city.