I think people bring up his catching ability because it's something than can be taught. Coaches can work with a player to help improve that area. Now on the other side of the equation, you can't teach speed. Wallace has this because he was born with it. You can't teach or coach Hartline to be as fast as Wallace. Ain't gonna happen. I know there are drills you can do, exercise, or the speed camps in the off season, but realistically - you can't teach speed.
I think with the right coaching, Wallace and Tannehill will get better and become a scary combination for defenses.