Pre-Orders are a great idea that was abused beyond any reasonable measure, not unlike DLC.

Being able to put money asside in advance on games is convenient. It can also show that smaller studios may have more interest in them then they originally realized, allowing them to make more copies of a game and keep it from being a small obscure release.

But then AAA studios had to start pushing pre-orders, and even locking content behind it, ruining a good thing for everyone.