A project because he's got multiple things to learn to have any consistent success at the next level. There's def more than one hole in his game. He needs a counter to his spin move, he needs to get off blocks better in the run game instead of just chasing the ball and so on. These things are very coachable but even then his upside based on physical size and speed limitations isn't as high as I would like given the compatible talent at his and other positions at that pick. Could have easily traded back and maybe still have gotten him, lamp or one of the other pass rushers.
When they use the word "project" for an NFL prospect it usually refers to a guy that has abundant raw talent but is not even close to having a pro skill set.
That's not the case with Harris, he's more in the "needs polish" category, which is pretty obvious when you watch his tape. He started late in football, junior year high school, so he's behind the curve in terms of technique and game awareness.
But you know what? That's a reason to like Harris MORE! He's had a good amount of success against the top competition in college football based mostly on his natural gifts and relentless work ethic, this is a guy that has already been productive while also having TREMENDOUS upside! He also happens to play a premier position in the league, he also happens to be coming to a team that has a player with a perfect skill set to match what Harris needs to learn, he also happens to have an electric first step that you simply can't teach.
Also, you're "one move" theory is is flat out wrong. Harris already has a decent rip move, and although his swim needs some work it's at the very least functional, so that's two right there. Even better than either of those moves, is the move that is required to have a great spin move, and that is a FANTASTIC speed rush. See, without the tackle having to fear you simply running straight by him, the tackle would not over commit to the backfield side, which is what makes a great spin move so effective. So any player that has a great spin move has at least two moves, and Harris has more than that.
One last thing; people have been talking constantly about trading back with Atlanta, but I've not heard anyone mention one key thing about that: what position did Atlanta draft after they moved up? That's right, the very same position that the player we wanted plays. Can anyone be sure that they wouldn't have taken Harris? I don't want to hear the "we could have ended up with player x", because Harris is obviously the guy we wanted, and with that being the case there is NO WAY you let a team targeting your player into your draft spot.