In what game has that ever been done?
Actually, many RTS's have released about all the info you could want before release.
As to the OP - while it is still uncertain what we'll actually get in civ5, I do agree how it's been marketed has been rather immaturely. One problem that I guess 2k didn't anticipate was the huge backlash by random people over Steam, arguing over that or reneging proposals or whatever has caused a lot of trouble. I think some others have complained about the kind of condescending, American-centric themes in various info blurbs released. But it's not a big market shooter game to advertise anyway, didn't do a public Beta or anything but that's not entirely expected again, and at least people have heard/are familiar enough with the franchise, so I'd say the process has been average as a whole.