Kinless Chronicles talks about something I think Blizzard has done exceptionally well with the latest expansion: "equalized content." Their story is about taking control of a Blightblood to finish off Drakuru, but there are countless examples of this in Northrend, from the last fight of Drak'theron to the encounter in Eye of Eternity with Malygos. World of Warcraft (and MMOs in general) has always been about levels and gear -- get better gear or level up, and you can cast more spells, swing an axe harder, and move on to more epic encounters. But Blizzard's "equalizing content" means that gear isn't always an issue -- by putting you in control of something else, whether that be a mind-controlled Troll or a siege vehicle, you can have extremely epic encounters without worrying about whether you're powerful enough for them or not. The limiter becomes not gear but skill (and/or the knowledge of how to use those skills).
Obviously they can't do nothing but equalized content, otherwise we're all just playing the same game (and, under pressure from players, they've even moved on to a mix of both, where gear does affect how you play in a vehicle). But Blizzard has really hit on something brilliant with what we're calling "equalized content" here, and used in a balanced way, it can allow players of all kinds of different skill levels to do even more epic things than they'd normally be able to do.