Depends on how controversial you want to go. Sexual references? Violence? Blood? Drugs? That's not that bad. While games have influence on people you've got to have mental issues if you try to emulate anything of that in real life.
But there is, of course, a limit to how far you can go with portraying something controversial *cough*rapelay*cough*
Over 100 years ago, movies had the same issue, and now, movie buffs have inception, citizen kane, and so many other greats, gamers want their medium to have its own citizen kane. And the timing is right for one to finally arrive. All gaming needs is a developer with a huge amount of guts and thick skin, and gaming will truly become a permanent fixture.
Video games develop the opportunity for individuals to explore topics where they place themselves as an actor involved in an issue. A video game can do as much to desensitize some to violence as it can to expand empathetic response and place people into situations that may seem truly alien or foreign.
Controversial ideas are something that's very good for video games. It gets these ideas out to usually a good group of people who will accept or deny these ideas. Videos are a good medium to test if controversial ideas can be accepted in today's society. It wouldn't be so bad for video games to embrace some of the possible future.
People hate new things and people hate new forms of art. Video games are a new art form, and people have to understand this to understand the opposing view points. All art should and can tackle important and controversial topics, and video games should not be any different than those.
Video games should avoid controversial content and content that may not be suitable for general audiences. One of the most interesting things about apps is that they have demonstrated that clean content can be very popular. As an example, one of the most popular apps is Candy Crush Saga. Violent video games have even been used by criminals to train for shooting sprees. If at all possible, video game and app makers should strive to create content that's clean, fun, and appeals to the masses.
Video games should not embrace controversial subjects, because there are too many children who are impressionable who play video games. Many children who spend a lot of time playing video games do not have very involved parents who are willing to self-monitor content. Video games should just be for fun relaxation, not for controversial topics.