I have recently been reading a variety of forum threads concerning Cataclysm and noticed an interesting trend. Many people like to state that they know their class the best, because they've been playing it "since day one." I think that's a funny thing to say, considering that most classes barely resemble their original forms. Hybrids are now capable of tanking and doing damage, and many classes have more than one viable tree for both PvE and PvP. Even the basic playstyle has been drastically altered, with Blizzard moving more and more classes to the reactive model of DPS instead of the fixed rotation of previous years.
I firmly believe that rogues have changed the least over the past expansions, when compared to any other class. Our basic playstyle remains unaltered, and the majority of our new abilities and deep talents are cooldowns or trick attacks: Mutilate and Envenom are the only two new abilities that we've added to our rotation repertoire. Assassination's 51-point talent is so bland that Ghostcrawler confirmed it's being yanked in Cataclysm. What is it about the rogue class that makes it so resistant to change? I think that we had a very solid original design, coupled with several unique mechanics that make it impossible to flex the rogue experience without breaking it entirely.