The system is nearly perfect, however, in TWW we should allow tier upgrades like this:
Explorer>Adventurer>Veteran>Champion>Hero>Myth
The system for upgrading could be unlocked halfway through a “season” for a certain crest amount (30-90 crests). This would allow certain world quest items as well as gear people collected in normal raids or low level M+ to scale upwards, provided you farmed crests in higher content. Locking it to halfway through the season could prevent abuse/slow down progression.
Pretty annoying when I can’t get certain items to drop the entire season with 3/3 vault for Myth, when I have 300+ aspect crests and wyrm crests burning a hole in my currency tab.