Maybe not invalidating previous patches within a expansion with the addition of each new patch? It's kind of interesting to see how insistent Blizzard is to funnel players into the newest raids, dungeons, zones etc. It's like they've become so afraid of Naxxramas 2.0 that they're willing to just throw whatever the fuck they worked on less than a month ago, just to make sure everyone experiences the newest new.
Why would a new player be anymore interested in Hellfire Citadel than Blackrock Foundry? Both are completely fresh and new content for said player, and Hellfire Citadel isn't even necessarily any better/more fun than Blackrock Foundry was. Generally this philosophy bugs me, but it's up to Blizzard.