The question to ask yourselves is this:
Can Wladimir recover from his brutal knock out defeats if
1- He was in an era of massive punchers:among the Lennoxes, the Ruddocks, the Tuas, the Tysons of the 90's
2- If he was 6'2 instead of 6'6
3- If he didn't have one punch KO Power.
The answer is no.
Wladimir glass boy is able to become a top 15 HW ATG because his era lacked elite punchers. After Sanders, He realistically only fought 2, PETER I and Haye. Against Peter I he was down 2 times and was in serious trouble at varoius times during that fight. Haye was a big puncher, but had a glass heart for that fight. Wlad is also 6'6 245 which means he can use his physical attributes to protect his glass chin.
Perhaps most important of all, Wladimir himself just like Lennox have true one punch KO Power, this is a great protection for weak chin fighters. When you got that one punch KO POWER, it takes away a lot of pressure.
Khan is in a division full of big punchers, he don't have massive physical advantages AND don't got elite KO Power.