Kane does have it all to prove. He's a class player but what if he moves to Real and can't handle the pressure and isn't scoring as regularly as he was for Spurs etc. It is one thing being a great player in a team which isn't really expected to win trophies and another when you're playing for the big clubs and expected to deliver week after week without fail. The pressure level is different. I'm not saying Sanchez can't handle it, just saying Hazard has definitely proven himself as one of the EPL greats.. not sure that Sanchez has and now he has the chance to prove he is right up there himself.
If the question is who would I rather United buy? the answer is Sanchez. His mentality, his endeavour and tactically he's a better fit for us. Question is who is a better player and for me..
If you put Sanchez in those Chelsea sides, I genuinely don't think they'd be as good as they were with Hazard in the side in full flow and at his best. They'd still be title contenders but not as dominant as they were with Hazard in the side. Hazard has lower bottom levels, but he has that lazy genius mentality but at his best.. he's been different gravy to anyone in the league. Internationally he hasn't been able to cut it, but Belgium as a whole haven't and lack of a good coach/mentality has been an issue, whereas Chileans are fierce as feck, with a great football philosophy to back them up.
I don't think its impossible for Sanchez to prove he's the better player. Just saying right now, I'd give it to Hazard based on what I've seen from them playing week in week out in this league.