I've been playing since around the end of Burning Crusade. Back in the days before the heirloom items that made leveling so much simpler, back before the 51-point talent trees, and back when a warlock with a fel guard could just spam shadow bolt in kara and still pull fair DPS. Then 3.0 came out and I was confused, but I liked what I saw. The 51-point trees made things a bit more complex, sure, but we got all sorts of awesome spells. Right near Halloween, too!
With 4.0.1 released yesterday, nearly everything has changed. Talent trees were simplified, ammo and soul shards were removed from the game, badges and emblems were converted to justice points and gold, the graphics have been improved, and the tooltips were edited a bit (see Soul Link).
I like to tank on my Death Knight in particular, and the fact that a dedicated tanking tree has been implemented gives me great joy, not only for the fact that I don't have to noodle through each tree to see what works best, but also because there won't be any more debate about whether blood is better than a frost/unholy hybrid like there has been on my server as of late.
Also, shaman tanks anyone?