A problem we face where I work is how designers sometimes limit themselves in the creative part of the work, because they don't know how to implement it later on.

Another complaint is that, if they have to implement something that's hard, that churn of work to do the actual thing ends up taking a toll in the design process.

Of course these problems can be circumvented but I think we're not the only place having this kind of problems.

I agree with the author, one day we'll all be teaching people to be at the middle of design and implementation.