That is opinion though, as other people have done the same thing and still enjoy the game in spite of it's flaws.
Sure.
There are people who buy a car based on the colour, not on the technical details, too.
Fact is, there are many people who were relying on the reputation of the developing company and pre-release promises.
As we know by now, almost any of these promises has not been fulfilled, putting the advertising very close to blatantly lying.
As you said: some people are more excited about having something new and shiny than promises and expectations to be fulfilled and met.
If you are the type of gamer who will take it upon yourself to analyze and accurately calculate the cost/benefit ratio of converting all farms to trade posts and arranging alliances with city states instead, you are NOT the casual gamer.
Unfortunately, they (2K/Firaxis) announced pre-release that the game was aiming for satisfying the "hardcore gamer", too.
Since this kind of "hardcore gamer" was mainly what is described as long-time fan, they collected the money from these players, and then openly admitted that the focus had changed and the game was more designed to appeal to the mass market/casual player/play-once-and-leave-it-for-something-exciting-new.
Not only this, but as having said before, promises were given, expectations were risen and almost none of them were fulfilled or met.
Just to name few items:
Combat AI: weaker than words can express
Diplomacy (the thing all these "pretty" leaders are about: opaque, to say the least
Graphics engine (was praised to have been created from the scratch, with the assistance of Microsoft, to be tailored to the needs of the developers; furthermore was said to be scalable): very hardware demanding with very little in return
Multiplayer: AFAIK, doesn't work for non-standard release civs.
So, many things aren't working or at the very least severely flawed. And this is two months after release.
But, there are self-proclaimed "defenders" who articulate to be tired by these things being mentioned, who accuse the people who point these flaws out to be "endangering" the future of the franchise and what not more.
*I* say, these things cannot be mentioned often enough.
As long as the developers are not able, willing or funded enough to make the game meet the advertisings, we should not let them go with such a weak product.