It's really just punishing people that want to get seals, which is REALLY bad considering there's multiple things you can only get with GC seals and they're quite in demand either for crafting or relic/etc.
There's multiple ways to get gear in this game and if dungeon gear was really that important, then it wouldn't be available for GC delivery in the first place. I think it's just overcomplicating things and it's not necessary since there's no cap on dungeon loot.