Berlin is liberation. Architecture, man!
User-centered design means understanding what your users need, how they think, and how they behave - and incorporating that understanding into every aspect of your process.
A good designer can create a design that accommodates all the constraints and still delivers an elegant, satisfying experience to the user. A great designer can go beyond this and create a design that demonstrates that some of those constraints weren’t really there to begin with.
I'm not sure that you can say definitively that some roles are better filled by consultants, but I would say that some projects are better handled by consultants.
Problems with visual design can turn users off so quickly that they never discover all the smart choices you made with navigation or interaction design.
But the best teams I've encountered have one important thing in common: their team structure and processes cover a full range of distinct competencies necessary for success.
Effective communication is a key factor in the success of your product.
Unless I'm writing in the Igbo language, I use a language developed elsewhere, which is English. That affects the way I write. It even affects to some extent the stories I write.
I can write a song in the back of the bus, where I am right now, or in my living room, and I can perform it that night and have an instant reciprocal exchange - an emotional, impactful exchange - and it's a less technical medium. It's a pure expression from my soul to other souls.
We must no more ask whether the soul and body are one than ask whether the wax and the figure impressed on it are one.
Whatever you have is gonna die and you are gonna have to rebirth something new. You have to be willing to ride the waves.