It's not the marketing professional's job to make the game be that good, that's the job of the developers. See, marketing folks can only talk about what they are told. If the marketing department downplays the game or its features, prospective players will immediately assume the game is trash. The marketing department also has to make sure the press is excited about the game. But here is the problem, the catch 22.
Players ask questions on the boards.
They want answers to those questions. Players hate that. And actually, so do developers. Players also hate when developers talk about systems in vague terms and of course hate when they talk about a system that does not come to fruition or is not exactly as the developer described. Players also want to know what we are working on next.