Very good question. I haven't looked into it closely, but I haven't noticed a significant pattern. When someone hits, drafted or not, we can typically look back and say, "Oh yeah, of course." We can look back at Chris Harris Jr and say, "He's not the fastest or most athletic, but he showed amazing instincts and coordination at Kansas, and he was all over the field."
In general, I'd say guys who don't fit prototypes but have some elite trait are probably the most likely to slip through the cracks when they shouldn't, but that comes in many forms. P. Lindsay was very good at Colorado - with excellent vision, receiving ability, and speed. He was just old and short.