I think the sterotyping is good, as long as it is done with an original twist. If there were no stereotyping of the lead characters the whole games shelf would be variants of the sims, average people leading average lives. Games need to push the realms of normality to make them appealing. I wouldn't buy a game where the lead character is a middle aged balding man who drives a bus for 40 hours a week. To me, so long as the storyline, characters are new and appealing the fact that they are not believable does not make the slightest difference to me.

Even the earliest of games were completely unbelievable yet they are the most successful of their times, look at the Mario series, 2 plumbers from Brooklyn end up in some twisted world with a toadstool for a friend or sonic the hedgehog rolling around the set at the speed of light collecting gold rings then fighting all sorts of monstroseties.

You could carry the unrealism arguement on for lots more, like films, superman, spiderman, xmen etc, none of these exist yet they have brought enjoyment to so many people that have watched them, purely because it is entertaining and you will find every avid viewer/fan relates or is in awe to be like one of the 'heroes'