n game ads are only going to be a concern of people who have nothing better to do than jump on whatever hate bandwagon is the in thing (Fileplanet, Starforce, Jack Thompson, MMOs, Horse Armor).
Adverts alone may, or may not drop sales enough to counter the extra revenue from adverts.
But, they [i]will[/i] drop the perceived product quality and value and this will be enough to drop at least some sales (mainly when added to other factors, i.e. where the purchase decision was already marginal*).
Many game buyers dislike the concept of advertising in games, particularly when they dont see any substantial benefit. Three primary reasons:
- scepticism that it will degrade the gaming experience somehow;
- perception that EA is getting a better deal. Even if people are no worse off, if they believe the other party has become better off they want a cut and anything else would mean they're getting bad value;
- people dont want adverts on things they have paid for. advert-free things are premium, things with ads are free - Adverts are a nuisance which people pay to aviod.
Note I dont say the game will actually get any worse, only that some people will perceive it, and perceptions are what decides purchases.
* BF2142 is a case in point. Many Battlefield players are already very unhappy with the franchise, and Quake Wars is shaping up nicely as an alternative. In-game ads are another reason to make the switch.