Hmmm....I would pick Wlad because by 1990 Big George Foreman would have found it difficult to catch him.George was never a speed merchant but in his second career he had slowed down considerably.
I’d pick Klitschko to be honest. While 1990 foreman might have been better than 2003 Sanders in SOME ways, the styles were completely different and took Wlad out of his game. Foreman would probably survive the distance and land a few good shots here and there but he didn’t have the hand speed or the awkward southpaw stance to do to Wlad what Sanders did.
I'd go Wlad even though he hadn't developed his final Steward style. Sanders was a speed merchant with a fast and accurate straight left that often took opponents unawares. Foreman had the clubbing power but was easy to see coming by contrast. Klitschko likely wins a somewhat uninspiring UD against old man Foreman who would tediously plod forward to exchange jabs with Wlad. Mind you, Foreman's jab was a hurtful punch and if he managed to land enough Wlad would not have a fun night either.
LOL,Comeback Foreman was never ever under any circumstances taking that fight............ For example, Tyson and Ruddock would have put that version of Cooney to the morgue straight off the couch in the first round. That was the absolute worst version of Cooney that has ever entered the Ring, a literal Mirage.