I think that would still be valuable though- If you (the interviewer) had done your homework, you should be able to recognize these concrete implementations, an

I think that would still be valuable though- If you (the interviewer) had done your homework, you should be able to recognize these concrete implementations, and ask the interviewee to elaborate on how they might improve the design. Best case the interviewee starts innovating a bit, and you get a glimpse into his/her design process. Worst case it becomes clear that the interviewee can only follow patterns that he/she is already familiar with.