My experience to date has been a bit difference - the person asking the right question needs to be a high-grade philosopher, the people trying to answer it only need enough high-grade philosophy to understand-in-retrospect why that exact question is being asked. Answering can then potentially be done with either math talent or philosophy talent. The person asking the right question can be less good at doing clever advanced proofs but does need an extremely solid understanding of the math concepts they're using to state the kind-of-lemma they want. Basically, you need high math and high philosophy on both sides but there's room for S-class-math people who are A-class philosophers but not S-class-philosophers, being pointed in the right direction by S-class-philosophers who are A-class-math but not S-class-math. If you'll pardon the fuzzy terminology.