Ofcourse, load pull analysis is an important step without which you don't know what impedance - power to match, but the small signal response is necessary as well. Initial design methodology always goes through small signal response (small signal stability analysis). This is purely a standard academic design process point of view. When the designed PA shows instabilities, you will have to backtrack. Not everyone has the resource to do a large signal stability analysis, e.g NDF, Nyquist plot analysis or even a HB analysis.