Honestly, I think Borderlands 3 is at its best when the loot makes you want to keep playing just to see what ridiculous build you can come up with next.
There's something satisfying about finding a legendary that completely changes how you approach combat. Suddenly, you're experimenting with different skills, farming for better gear, and replaying encounters because the weapon itself makes the grind enjoyable.
That's why I don't think every progression system needs to be packed with extra challenges, currencies, or repetitive objectives. Vault Card keys can give you another reason to play, but if earning them starts feeling like a chore, the reward stops being exciting.
The same goes for side missions. I don't mind a weird or ridiculous quest if it has entertaining dialogue or an interesting payoff. What annoys me is when a mission stretches a simple task into a bunch of unnecessary traveling and waiting.
Borderlands is a looter-shooter. The loot should make the grind fun, not become an excuse to add more grinding.
What's one legendary weapon in BL3 that you keep coming back to, even when you have plenty of other options?