Case in point here is the essential balancing element between the classes in terms of how they perform versus one another in PvE and PvP. Looking at the current state of things on the beta, many people have been looking at the amount of balancing work left to be done, then looking at the time Blizzard has left to do it, and thinking that our favorite little company that could isn't going to make it.
Then again, most of the people saying this are players of one particular class or another. Very few have the ability to stand back and see all the classes at once from a very knowledgable and objective point of view, how they interact with one another and what their various strengths and offsets are. Most players see the entire game from their little own little vantage point, and are apt to view their class's shortcomings as serious failures of game design rather than areas in which they'll need to get their friends of other classes to come help them and work as a team. Sometimes, after playing for a while, the general playerbase realizes that the huge nerfs everyone was yelling and screaming about just a little while ago aren't really that bad, and the game is still very enjoyable regardless.
What do you think? Are the classes going to be balanced by the time the expansion goes live? Or are the actually more balanced than they seem, even now? Is it going to be a huge disaster with just a few classes stomping all over the others, or is Blizzard going to pull some magic rabbits out of their hat just in the nick of time? Will we see tons of post-launch minor adjustments, or certain classes just languishing for months at a time, or will it all turn out to be okay pretty much from the beginning?