1st Level, 2nd Level, 3rd Level etc etc always seemed simple and intuitive to me? It's just 1-9 (or 0-9 counting cantrips) with 1 being "weakest" and 9 being "strongest". So I don't quite see where confusion could stem from.
Also 4e arguably had tiered progression for every class, you had your level 1 daily, level 3 daily and so on, and the higher level ones supposed to be stronger. And I'm one of the few who likes 4e and notices 5e did port a bunch over in and melded it with 3.5e...
