I fancy Sanders. Faster, more accurate, more aggressive. That said he did have the flaw of maybe being too aggressive. He sometimes got caught trying to finish a guy. If that happened against Zhang, well, very no bueno.
I think you nailed it. One thing that stands out about both guys is Sanders had outstanding hand speed for a heavyweight and Zhang does not. What Zhang does have is better durability and he seems to fight within himself well where Sanders could get over aggressive like you pointed out.
Whoever lands first is likely to take it, in my opinion anyway. I do remember in Sander's first loss, I think Nate Tubb's times Sander's with a big right hand and had him almost out cold. Have to imagine Zhang could change the trajectory of the entire bout with one punch.
Sanders was a better fighter with some very good tools he could use against Zhang. Problem is his stamina was poor and his chin wasn’t the greatest. I could see a scenario where he gets stopped mid late rounds
I'd lean towards Sanders. The thing is, he'd drill Zhang. It's a foregone conclusion. Zhang would have to take it and land his own shots in order to win, but his stamina is basically too crappy to do it after the first six rounds. I've seen both in person. It's night and day. There's no way to accurately describe how much faster Sanders was.