Despite some of them being rather controversial, Add-ons are an inherent part of Classic by now and most of the players can't imagine playing without them. Despite the fact that some vanilla veterans despise add-ons, there's no arguing that they make the game better by adding a lot of customization options and quality of life improvements - there's an irony here: players had wanted no changes, and then they've changed the game with add-ons anyway, sometimes to a point where Blizzard was forced to ban some of the more invasive add-ons. While Add-ons was not a major thing in vanilla, they have certainly made a great impact on Classic.
