Basically the title. I think it would be very fitting for Faker to get a legendary skin. The legacy he has behind him and being the face of LoL Esports for almost a decade he deserves to get a legendary skin for a legendary player.

Also given that the SKT skins were released in this price order it also fits:

2013 - 750 RP

2015 - 975 RP

2016 - 1350 RP

2023 - 1820 RP

Faker was the only one in all of the winning rosters and just by his status alone he would be worthy of a legendary skin.