The more boards, the less value.
I personally don’t think that these boards don’t produce nearly enough daily volume to be separated into sixteens and expect to survive.
I realize Core is using phpBB and is slave to its capabilities, but the best solution would be to have a Main board that tracks all of the other boards (like a “view all”.) This would mean I wouldn’t have to peek into 16 different boards to join into conversation threads (something I don’t have the time or energy to do.)