Simple? Yes. Effective? Definitely! The Fleeing Crab is a standard in our area and is at least partially responsible for lots of great fish pictures. The lead eyes will get it down and help it to ride hook-point- up. Rubber legs out the back wave and wiggle in the slightest current. We have found the Fleeing Crab to be at least as effective as many of the much more complex crab patterns.
Try the black versions for black drum. The Sand/Tan is great for spooky bonefish, as are "Merkin" and "Blue Crab". Reds will eat them all!