But FS and especially PAD speed is really important first.
After that it is in fact DS that separates the guys that stay vs. the guys that go in the first cut.
After the first cut, its the guys that have stamina, conditioning ability, physicality.
BUT, you are correct that at times, coaches GUT instincts trump everything and in the end, a lot of NFL position coaches are still prejudicial towards players with whom they have a connection (Alma Mater, Conference, and Eye Test prejudices).