What would you bring back?

As expansions come and go, some features come into play, exist for a while and then are retired, or never actually make it live - reforging comes to mind as a big one, a feature that was of critical importance for two expansions before it was removed. While flight itself wasn't removed, it's of no utility in Draenor's 90 to 100 zones,or world of Warcraft and mechanics like hit and expertise, weapon skill, and others have been removed over time. Raiding has fundamentally changed repeatedly. Talent trees are almost unrecognizable from the old days. Several old dungeons and raids were removed or revamped, with their original versions gone from the game.

So this morning I ask you this - if you had the power to bring back anything from any era of World of Warcraft or its beta periods, what would it be? Would it be Naxxramas 40 player? Reforging? Weapon Skill? Path of the Titans? Please share your vision.