If the inner surface of the ileum in the human small intestine was smooth, rather than being folded and subdivided into villi, humans would have needed to evolve a much longer? 

Concept: If the inner surface of the ileum in the human small intestine was smooth, rather than being folded and subdivided into villi, humans would have needed to evolve a much longer small intestine.
Under normal conditions small intestine has small finger like projections called micro-villi, these villi provide large surface area for efficient absorption of food, but if these villi are absent then the length of small intestine should be longer than now for efficient absorption of digested food.