Since we agree, that the Ahl-al Sunnah Wal'jamaa'a is the aided and saved firqa, stands firmly on the truth till the day of judgment. Then why don't the Ulama and thinkers of this group make an international convention and declare to the whole world on TV news media, Internet etc. that authentic and real Islam is represented and reflected only and only by Ahl-al Sunnah Wal'jamaa'a. All other factions who claim to be Muslims are false, invalid, distorted creeds, innovators, and deviators from real Islam. So, the non-Muslims will really know who are the real Muslims and who are not!
Some non-Muslims who are interested in learning and converting to Islam get really confused when they find out about several factions, all claim to have the real Islam!

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

What the dear brother has suggested is impracticable for many reasons. For instance, sometimes the scholars of Ahlus-Sunnah themselves differ in some matters. However, this difference of opinion does not have any effect on the truthfulness of their methodology.

Indeed, the acceptable difference of opinion is permissible in the Sharee’ah and this happened between the Companions . This is the Wisdom of Allah but they all agree on the principle of the religion and belief and about the matters where opinions are not accepted by Allah. The truth is indeed evident for the one who wants to know it.

All the Muslims are obliged to abide by what the Prophet and his Companions were upon, and they should call the people to that in a gentle way and good manners without forming a party or being partial to any specific group (being fanatic), and they should not bind the truth to a given group. Rather, Ahlus-Sunnah are not limited to a particular place or country, or a particular group or sect, but they are those who follow the way and the methodology of the Prophet and his Companions in belief and deeds regardless of the place where they live or when they lived.

Allah knows best.