First of all,according to the same gold farming guides that have extensively studied the beta build of the expansion, the ability to make fast WoW gold can be expected in WotLK. There's one beta tester, for example, who started with 50g going into the expansion, and ended up with 2,000g at level 73 without doing anything special other than questing and selling his loots.

Secondly, according to advance copies of updated gold farming guides available at Gold Farming Guides, the existing dailies from the Burning Crusade will still be in the game.  When they're tired of leveling, gamers can revisit the Outlands for these dailies to continue earning rep and gold that will help them in their continuing adventure in Northrend.This means that the player can still visit the Isle of Quel'Thanas, Skettis and the Blade's Edge Mountain to get their 25 allowable quests per day for some 300g or so every 24 hours.