Each room has a geometry, a form and a size, and a topology : some openings like doors and windows, and each room has an acoustic content with various properties: a wood furniture dont work acoustically like a rug or a piles of books etc...
Speakers placement so important it is , is secondary to mechanical room control...
Because you can modify the room pressure zone distribution for example with Helmholtz resonators and diffusers and compensate for the geometry and topology of the room and for his acoustic content and even compensate for the speakers needs and the room itself, all of which problems can never be solved by repeating the common place fact about the importance of speakers placement...
Speaker placement is not enough, it is only the FIRST step, the second is passive treatment, and third and the most important for small room , mechanical control....
However, as important as these things are,for me,speaker placement was the most important factor.