It just seems like people are describing faction leves over and over. I'll explain it for those who don't know how it worked.

Back then, the adventurers' guild was just distributing leves for factions that needed adventurers' help. There were of them: Azeyma's Shields, Brotherhood of the Broken Blade and Horn and Hand. They worked almost exactly like leves do now, and upon completion would award faction points for the faction of the leve.

Faction points could be traded for faction leves. Some were in a series, if you finished one you'd unlock the next. At level 50, there were many fun and diverse, sometimes difficult leves. Killing two NMs at different ends of a map in a short time, killing a huge magitek vanguard boss, etc. These dropped some pretty valuable gear (which together with pretty much all other once-useful gear has just been thrown into Dzemael coffers). They were completely open-world, challenging, fun and varied.

Sounds just like what so many are asking for.