The tactical differences seem fine to represent the struggle in the samnium, but in the strategic level (besides tactical advantages). Would the samnites cities be easily put under control once occupied? or would them be prone to rebellion? The proposition about a separate culture for them was just to represent the ardous strategic work that SPQR took building fortresses and putting heavy garrisons all around the samnites because their cities won´t be easily subdued. But i really do not know if it is neccesary to make Latins and samnites two different cultures to achieve this in the game, but i guess it would be easier than other ways.