You can be disappointed with publishers' crappy pre-order incentives. Or you can do what I do and just not buy the game at launch. Most of the time, players will report back that the pre-order DLC is pointless and skippable. Then you can happily buy the game without worrying about any pre-orders.
And if the DLC turns out to be good, buy it separately. I can't think of any recent game that had exclusive pre-order content.