I'm surprised it hasn't happened earlier. gaming is big business now and so far the psychology of games/gamers has been largely empirical, partly because it's still relatively new, also because of an inherent social prejudice against gamers (after all, it's *only a game*
) and it simply hasn't been taken seriously enough. Developers have had to rely on their own experience and likes/dislikes and translate these into something with mass-appeal.
There should be enough raw data now though for a thorough scientific analysis of what makes "gamers" tick though, a study which is now being seen as essential to the planned growth of this industry, as much as it is to the op industry or tv production or big-budget films. This will mean less wasted effort, fewer projects dropped at critical stages, and for the bulk of gamers, more of the things they like.
however - theres always an however, isn't there? - it might also mean a general levelling out of games, as standards and content might become more homogenised. if all game developers and publishers have access to the same data, and compete in the same market, might they not tend to come up with the same/similar answers? Every now and then there's a game that's highly original and pushes back the boundaries as it were, and sets a new standard; you may well see less of this in the future, as a lot of the gaming community is happy with pretty graphics, simple plots, and big guns.