I pre-ordered as a sign of trust. Now, I know that some of you would believe that it is highly idiotic, would chastise me for reckless spending, but I saw some other people in this thread who were like me. I trust Firaxis and 2k to deliver a high quality product, and did the same with Civ V and its ordering. Some are saying that they may sell-out with motives of profit in mind, but I do not believe that, with Sid still advising production and knowing how he designed things, the company is trying to negatively manipulate us with false promises. There are also people with the opinion that Civ V was crap, but it was brilliant in my own opinion too and in introducing the Civilization series to a whole new group of people. It is how /r/civ (referring to the reddit community for civilization) began to explode with people posting screenshots, videos, walkthroughs, and setting up multiplayer matches.
Nevertheless, I too see the issue in pre-ordering in that, despite the amount of trust involved, there is little power in the process to the consumer save maybe some general demand of the community to attempt inclusion of a feature.