You can continue to perform leg raises, crunches, curl-ups, rope pulls, etc. and very little will help improve the actual muscle belly of the abdomen. Most of the common ab exercises you see people doing in the gym do very little in overloading the abs. Most are hipflexor dominant exercises, using the abs as a stabilizer.
Furthermore, deadlifts, bench and other multi-joint exercises will recruit the abs far greater than in a casual crunch. The more musculature involved, the higher the stimulus must be.
Simply: drop the fat to the single digits, and naturally your abs should peak. The shape is predetermined.
KM