This should not be a revelation.
Stern already has hired someone that meets your criteria in terms of programming design since the mid 2000s.
He has provided design support on 16 Stern titles since 2005 (not counting any special editions or LEs).
His name is Lyman F. Sheats Jr.
He remains ranked as one of the world's best pinball players, when he decides to participate.
There are some videos that showcase his talent.
He was hired for a number of different skills, including his experience, creativity, enthusiasm, and his ability to play pinball.
When he was hired originally by BLY/WMS, this was a significant factor as well.
Many of the more popular games from the 1990s until right up to today can be attributed to his efforts.