It has to be easy to get into for the masses of casuals and newcomers to be fun. On the other hand its numerous combinations of perks, weapons and game modes allow for some "advanced tactics" if you want to use them. It's supposed to be fun. Other games may show more "depth" right away but they also scare people off much easier. You can play this as a single person or you can use a team and be very successful, there's always a choice. If you have to "work" to get into a game, if you have to have all the fancy unlocks to make if fun, if you have to have your buddies back you up to succeed... well that can be fun also but it's not as convenient and nothing for the masses of players out there. At a certain age, time becomes precious If you need too much of it to have fun with a game it doesn't work well for the "older" crowd (just like the ADD youth, what a mess).