It reminds me a good old tips : "Try, Fail, Learn, Repeat".
This article is very interesting in the sense it is specifics to game design experience. However, I really think it just apply to life in general.
In other words, how fast you can iterate, and how much trust you have with your team to try new ideas, will dictate almost everything about how good a game designer you become. And this means: a game dev team with super-specialized roles and tools will create employees that have less value.