Basically I am wondering how loot drops work. I understand drops have a chance-to-drop, meaning they could not drop at all from a boss. But here’s my main concern. Lets say I get the quest “Animal Rights” from Mordecai at level 21, and I don’t decide to finish this quest until I’m level 35. Would that mean I have a chance to get the Trespasser (the sniper you can get from this mission) as a level 35 weapon? Or would it just be level 21?
Yes, but it’s based on the level of the quest not the level you accept it at.
(Flying: throwing yourself at the ground and missing)
@Piemanlee is correct. When you accept any quest, you’ll see the quest level on the card (which you can go back and check at any time in your inventory on the left-most tab.) The reward will always be at that level.
And you will get that item (or choice of items) as specified for that quest - there’s no random chance to whether or not you get a quest turn-in item, only what parts it might have. Example: The Heartbreaker (Safe & Sound quest) is always fire, but I recently managed to score one with a melee attachment.
When folks talk about drops, that’s different to quest rewards. All the bosses have a designated drop pool, and you have a 1-in-10 chance of getting an item from that pool whenever you kill the boss. There are some slight exceptions, such as killing the Warrior on the final story mission is a guaranteed legendary item from a set list (Volcano, Impaler, Flakker, …) but on subsequent farming runs it’s only a 1-in-10 chance.
You can read lots more about the loot system here:
Doesn’t the Dust (and the drops therein) scale to player’s current level, no matter which playthru one is in? The quests won’t scale but IIRC the drops will, which makes it a good farm as one lvls up…unless I’m wrong.