Brilliant. It might make it more realistic, but the money they make through the ads won't go towards anything for the game. With this, they could potentially knock of money for DLC. Will they? Not a chance! If anything, I could see it going up with the popularity of the game, just like CoD's has. If CoD had in game advertising, do you think Activision would sell the DLC for 800MSP? No, they'd keep it 1200 and make more money from the ads.
I wouldn't care about the ads, but it won't make anything cheaper or better for the gamers, so it doesn't really effect us, just the company.