Better ball control, better dribbler (Yes, he is better than Hazzard at what Hazzard is known for). Better passer, better vision, better defender, higher work rate. Hazard is quicker in and out of breaks, and scores more. But then again he has more opportunities.Average vision ( hence why he dribbles so much) decent passer, but not as good. Strikes the ball better, but makes more poor decisions shooting ( I.e. selfishly shooting off balance after 1 of his dribbling runs), that's why he misses a lot.
But the greatest difference is ball control. Isco is the closest thing to Iniesta I've seen when it comes to making a ball stick. He can control it at any height with ease. Hazzard in the other hand is at best decent.
There are other qualities Hazzard is better at, but they aren't quite easily quantifiable. I think he has a greater sense of confidence perhaps. And a belief he is the best player on the field regardless of what the facts actually are. I don't think Isco has that. But that is easy to develop.
In terms of Actual technical skill, Isco is better at almost all except for shooting, quickness ( not speed- as both are equally not top end speed wise) and Hazard's patented turn away dribble.
I'll take Isco everyday and Twice on Saturday.