I think focusing on convenience and cosmetics is the way to go. People with no money will play the game for the gameplay, populate the servers, and earn their weaps by putting in time (thus populating the servers). Casual douchebags like myself who have jobs and kids will be drawn to the high number of players, but will also pay to look cool and pay for new weaps instead of earning them over time, since we had kids and jobs. It keeps the game popular and keeps the coffers filled without turning people off.
Not that I personally play multiplayer competitive games. But I think the logic is sound.