Borderlands 2 made Ashley Burch a main stream voice actress, and got her a TON of public visibility, and she was in a lot of things after that game blew up. Not going to say she was totally unknown before that game, but it's definitely when I remember starting to see her name/face pop up all over the nerdosphere and gaming stuff.
It popularized that cell shading style of animation, that I don't really recall seeing very much prior to that game, but saw a lot more after.
It made the looter shooter a lot more marketable, as I've seen a lot of people compare CP2077 to Borderlands as far as the actual mechanics of the game, and what "progression" boils down to.
You started getting more "Charismatic Asshole" villains after Handsome Jack, to varying degrees of success, but they were there.