Probably see if the tactics are the issue. I'd hold on to him, at the very least, until the end of the season. Hazard is a monster. But yeah, other than that, Quintero, El Shaarawy, Bernard, Draxler, Stanciu, Januzaj.
if eden hazard, one of the best players in the world, is consistently getting a 6.0 rating, then you can be sure its something you are doing.
Im sure there are folks on here who could post a screen shot of Hazard playing as an IF on the left side with an average rating close to, if not above, 8.0.
Maybe he has no space to run into, maybe there is nobody to pass to, but changing players isnt going to do anything for ya if you dont know why you are doing it.