Just did a great experiment the other day.
Ive got two p-basses that needed some work. The rosewood fingerboard bass needs a refinish, so i ripped it apart to send out. It has lollar 10% overwound pickups in it. I love them, they are great! The maple fingerboard bass i have needed to have the seymour duncan quarter pounders replaced. I feel they have a very unpleasant mid frequency quality to them. Great highs, high output, good price, just not my cup of tea. I could never get the gross part of the mids out of this bass. Mids are EXTREMELY important to my tone, but some of them i dont care for, particularly the ones coming out of the duncans.
I swapped in the Lollars into the maple fingerboard bass, and would you believe that it now sounds just like the rosewood board bass. It was always my backup, but now with the right pickups, id have no problem recording with it. Strung it with TI flats and its a dream. All the other basses have TI rounds, i needed flats bass!
Ill be getting some aguilars or lollars for the refinish bass. Im OFFICIALLY in the camp that believes fingerboard material has NO impact on tone. Not looking to start any fights over it, just stating my findings!