I think it comes down to understanding what question(s) you as the interviewer are trying to answer about the candidate. If you’re honestly trying to see how someone goes about solving a problem, it really doesn’t matter what kind of problem you ask them about, you should be focused on what they do, not the solution they come up with. The problem, that I see a lot on both sides of the interview table, is when someone claims to want to see how a candidate solves a problem, gives them a problem, and then judges them on the solution they produce, not on the process that they used to produce it. And THAT is where what you highlighted in my piece comes into play. No one, not the best designer in the world, is going to be able to create a great or even good solution under those conditions except by chance. So, if you’re judging the solution your candidates come up with in that situation, you are filtering candidates by their ability to guess the correct solution to your company’s problem, big or small.