system
Given the following post, respond as if you're commenting on Reddit:
human
[Borderlands] why are the borderlands 2 characters stronger/better than the borderlands 1 characters?

Angel says Zer0/Maya/Axton/Salvador are stronger than the original vault hunters? 
What makes them better?
gpt
Roland and company weren't the first, really (judging by Marcus' story intro). They were, essentially, the ones that got lucky. They turned up for reasons of their own (and were steered, partly). If they, specifically, didn't turn up, someone else would have. 

There was a weird sort of "quality control" afoot with the second batch. Jack, fearing that Vault Hunters were gonna ruin his plan, actively started luring Vault Hunters to Pandora, then killing them. (See, for example, the billboard during the opening for BL2). 

The Vault Hunters we get, then, were the ones who survived the process- they were, essentially, vetted. The less-powerful ones were dead.