Why free to play games are inherently less fun
Designing a free to play game with microtransactions is a huge challenge. It is incredibly difficult to find the perfect balance between giving players a strong incentive to pay something while still making the free experience good enough that they keep playing. This challenge is crippling to the game itself. It is impossible to make a game as fun as it could be for both paying and non-paying players. At least one of those groups gets a game that is less fun. Game design is all about making a certain concept as much fun as possible. By tweaking things like difficulty, flow, reward systems, variation and complexity the game designer tries to create the best experience possible. This "best experience" is an invisible target: you can never know whether you have reached it, or whether tweaking some things would make the game slightly better. It is also something that differs depending on the target audience. Some players like a challenge, others like a more relaxed experience. So...