"Even the "Curse of the Flesh" isn't really a curse. It was bad for the Titans to lose their army, but the result was pretty good for the ones turned."
How was it good for the one turned? They lost perfect order and probably immortality (if you are a machine or stone, I don't think you'd die from old age). They gained death, war, famine, illnesses, being pawn in a war between being of unfathomable power (titans vs fallen titan [Sargeras] vs old gods vs lich king) and free will.

We, the players, as humans value free will pretty highly. But really, was it worth all they lost?

@Polibrun:

Sure it is. You don't know how "good" you have it until you lose something.

So imagine you're an immortal robot/rock monster, and you're only able to follow your pre-defined coding/orders.

Suddenly, you're "free", and severely lacking in the "gonna live forever" aspect. Sure, you may be pretty sad/mad, but (and this is just me assuming) those emotions? They're part of the whole "free will" bundle package (also included? Happiness and the whole lot). You don't get to feel sad when you're following your programming. You only get to feel what you're programmed to feel.

Why do you think the Forsaken are so pissed off? Their old lived were taken away, and they were put under the "programming" of another. They were also suddenly immortal, but what use is it? Sure, you can live forever, but what is the point in the long run? If you're immortal and don't have free will, you're just a tool in the end, something to be used and then set aside when the job is finished.

... or some such nonsense.