The advantages of setting the bar low :). The original Borderlands didn't really need much in the way of plot. It was basically one long fetch quest. Everything was about getting something so that you could get something else so that you could find the entrance to the vault... then some more fetching so you could open it and then some fetching so you could get actually get through the locked gates leading to the vault.

The second had an antagonist with a delightful personality, a rebellion story arc... (sorta) and a larger pool of characters with which to craft a narrative. There's a problem with the Vault Hunters you portray. They don't really speak. Even if they did, since there's no telling how many or which of them will be involved in a cut scene, how do you write such a scene's dialogue? It's not impossible but definitely more difficult.