There are alot of similarities and differences between shia and sunni manhaj.
Aqaid of Ahlul Sunnah manhaj are different from that of Tashayu. Which scholars made those aqaid? Were these Four Imams (Abu Hanifa, Malik, Shafi, Ibn Hanbal) of Ahlul Sunnah?
Sunni method of hadith collection is also different. Who is behind that method?
In short, who made the theoretical base of Ahlul Sunnah manhaj? He must be some influencial scholar who either wrote books himself or his students transferred his ideas into books.