Game design is an art in which science is very important.
The game designer can be compared to a wizard who creates a special reality for a player and a special experience.
It is important to be able to divide a wide stream of tasks into small streams and correctly distribute them according to priority.
Every year, it becomes more difficult to become a game designer without the systematic knowledge that is usually given in courses. This is explained by the fact that over the past decades hundreds of thousands of projects have been issued. And if you have not played before, you need to understand well what to focus on, what resources to read and what to use.
The game designer does not have to be a doctor of mathematical sciences, but must know the mathematical base.
If the game designer has not incorporated the trigger game into the economic system so that the analyst can look at events and statistics, the game will have to be redone.
Unreadiness to work with certain software is a frequent cause of refusals to get work from beginner game designers.
If you go to the "alien" territory - related or completely different genres of games, you can just find a new concept that will stand out in your genre.
If the game designer does not understand at all in any area, then he will set a very broad scope of the task - the scope of his decision will also be wide. As a result, the result will vary greatly: from complete unsuitability to "this is what I requested."