I know there's a lack of top 'traditional' strikers everywhere, but you just can't call a player world class when half our academy has better technique than him - and I'm being generous there.
Don't get me wrong, I really appreciate Diego. I think his movement is among the best I've seen from a striker, his instincts are good and on form his finishing is exceptional. But, in addition to his lack of technique, he's weak in the air, his ball retention is almost nonexistent and his decision making can often be well below the level of the team; he chooses to dribble so many times, especially on the wings, despite the fact that he's so predictable and bad at it that even the weakest defenders can stop him most of the times. But all that doesn't take away from the fact that he can be an excellent striker if we play to his strength.
To me, this is like when people were calling Matic the best DM in the world, or Thibaut the best GK in the world, almost no one without blue-tinted glasses thinks that. Doesn't mean that all of them aren't/can't be very good.