The debate over whether commoners or clans are more important is as pointless as arguing whether a chicken or an egg came first.
A clan is essentially an exceptional gathering of commoners, and from this perspective, it would seem more important to secure the allegiance of a clan, for it represents a selection of outstanding commoners. But, we can't just skim the surface while evaluating matters.
Tang Luo knows that it is almost impossible to change the present mindset singlehandedly, hence he chooses to discuss the potential of commoners with the aid of two more convincing noble families.