Here's how I approach pre-orders.
Forget about pre-order bonuses, save for proper discounts. I only ever bother to pre-order through Amazon because they frequently offer up $10 pre-order bonuses and I just recently scored a $20 pre-order bonus on Crysis 3. If a pre-order bonus is really all that, you'll be able to pick it up later as DLC. Usually they're not worth such consideration.
Treat it exactly as you would a DVD or a book. If you're so excited by it you must experience it on release, then pre-order it with whatever pre-order bonus scheme you like best.
Pre-order as late as possible so you're privy to any negative pre-release buzz. Turkeys in any medium rarely hit the shelves without a few warning signs. Cancel any pre-orders you have if you experience any kind of sinking feeling prior to launch.
If you're uncertain about the title in any way, wait for the reviews before giving them your money. If you're backed up on games, wait a bit, pick it up when it drops $20 a month later, then pick up any pre-order bonuses you fancy with the money you saved.
The problem really isn't pre-orders. It's companies doing everything they can to hide a turkey until it's too late, because there's simply too much money on the line to do otherwise. As always, buyer beware, and don't let yourself get suckered by a trivial pre-order bonus when you've got concerns about the underlying product.