Which mechanic from post-Classic WoW would you most like to see in Classic WoW?

Right, I know, #NoChanges and everything, but what about #OneChange? If there was one thing from a WoW expansion (i.e. 2.0 and beyond) that you could add to WoW Classic, what would it be?

For example, an element introduced in late Burning Crusade that has survived in one form or another since then is the Badges of Justice system. Doing certain kinds of endgame content generates a currency that you can use to buy endgame-quality gear, giving you a sense of progression and maybe helping you and your team get over a difficulty hump. In the world of Classic, where raiding only nets a few pieces of gear per boss for a raiding team of three dozen or more, such a system might help to make everyone feel like they’re getting something out of the boss kill even if they don’t get any drops.

Another example? The Followers system that was introduced in Warlords of Draenor and then saw iterations in Legion and Battle for Azeroth. With it, you collected followers through questing (or other kinds of content) and could then dispatch those followers on missions that took a number of real-world hours to complete. Provided your followers (and the nameless henchmen you sent along with them, natch) are able to overcome the mission’s challenges, they would come back with rewards that range from gold to gear tokens.

World of Warcraft has evolved to include a wealth of features over the years — and the game definitely has some interesting systems that didn’t exist in the Classic days. If you could add just one of these features to Classic, what would it be?