> feel that these types of interviews are inadequate at measuring a candidates potential

This isn't meant to measure potential. It also isn't to make you feel good about the process. It's to give the employer some assurance that the candidate can think through not only the problem but how to implement a solution. It's not enough to understand the theory and be able to write whitepapers about it. It likely exists because other candidates have got through the process but were not effective. It likely won't apply to you, but they just want to do some up-front filtering. If you want to find a research position that doesn't involve implementations as a deliverable, then perhaps you could apply for those if they exist.