It is actually. Like i said, Zlatan can do things that Ale is not good at, most of the things Ale can do Zlatan can do them too, just not as good as Ale.
For example Zlatan is a very strong player, DP's physical ability isn't that good. Zlatan is a monster in the air, DP can't compete with most defenders in the air. Zlatan is both a physical and a skillful player, DP is 95% reliant on his technical ability. Zlatan can lead the line and be the main striker like he is doing at Barca right now and at the same time he can play as a second striker that drops deep to pick the ball up and bring teammates into play, DP can only play as a second striker, he cannot lead the line or be the main striker.
Therefore Zlatan is a more complete player, but he is not a better player. Same as Ronaldo being more complete than Messi but not better than him.