For those of us who are leveling up or even digging into a fresh 80, there's never been a better time to fold in The Loremaster to the ol' to-do list. Flying your Loremaster title proves you've been around the block; it's not like The Explorer, which you can hoof your way through even at level 1. Earning your Loremaster title means grinding out literally hundreds and hundreds of quests over every step of your journey through Azeroth, Outland and Northrend, from level 1 through level 80. It's the completist player's dream, a title that shows you've paid your dues in every zone at every level of the game.
We're not bringing this up now as just one more item to chuck into your pre-Cataclysm bucket list; indeed, The Loremaster won't be going anywhere in Cataclysm. While none of the numbers of quests required for completion have been adjusted yet to accommodate Cataclysm material, Blizzard has assured players not to worry about it. The Loremaster quest count has been updated before, so we should be confident that it will be adjusted again.
Still, if you're playing through the old content anyway, it simply makes sense to run through quests that will be disappearing when the expansion cracks Azeroth apart at the seams. Sure, there'll be plenty of new quests to do -- but you'll never get the chance to run all of these particular quests again.