If it ain't broke - don't mess with perfection :)

Way too detailed to go into here - but my last company had a very structured interview process and I don't think we ever asked about past work experiences, etc. (The company is basically a group of Product Managers) Every interview is about problem solving - one of the steps is a stock options puzzle that really gets to the heart of the matter when it comes to personality type and how they will fit with the company culture. I've had actual options traders fail, I've had people get angry and argue. I had one poor guy hear the question, then stand up, thank me for my time and then leave without even attempting it. On the other hand, you get that person who is going to dig in their heels, tie a knot in the end of their rope, and not leave until they get the right answer. (Spoiler alert: we hire them)

Sounds like you are looking for the right people and are less concerned with specific hard skills. I wish more companies would interview hire with that mindset.

And would agree that humor in the interview process is sadly underrated...