Immediately after his loss to Young, Foreman gets an uncharacteristically generous title shot. He beats an aging Ali in whatever fashion you find most plausible. Foreman then retires like he did in our timeline. He returns 10 years later, beats Moorer, and basically has an identical 2nd career to his real one Ali is simply re-granted the vacant title. He *also* fights all the same people, with identical results, as he did in reality. The only difference between this timeline and the real one, practically, is that Foreman has an older Ali victory on his record, and Ali has a L to post-Zaire Foreman. Where do you rate Ali and Foreman in this scenario?
A more likely scenario was Norton getting the decision he deserved over Ali in their 3rd fight and then defending against Foreman. George then rematches Ali, I believe that version of Ali was a shell and a more disciplined Foreman beats him. Would it change my opinion of either man? Not really
For me, it would raise my opinion of Foreman quite a bit. I currently think he is often quite overrated as I have him on the edges of my all-time top ten. I could see him being bumped up to seven or eight. I thought Ali would lose to Foreman when the fight took place and I was never more happy to be wrong. I probably would have picked Foreman to win a rematch anyway so my opinion of Ali would not really have dropped too much.
That would then mean that Foreman had a better first career and the same second career. Foreman would add Muhammad Ali to his resume, and that is very important. And he would become a three-time lineal champion, which is also important. That would happen before the Muhammad Ali-Leon Spinks rivalry. IMO Foreman would move up on the ATG list; at least one place.
That something fishy was going on because Ali is a terrible matchup for Foreman, so a loss for Ali would mean he threw the fight.
Losing to Jimmy Young did Ron Lyle's title shot no harm, so it seems fair that a former champion was afforded that same treatment....losing to Lorenzo Zanon did Alfredo Evangelista's shot at Ali's title no harm either... and that was in 1977 too, so in this scenario George's title shot while 'generous' isn't quite 'uncharacteristic'. Ali's rating would about be the same, Foreman's a little higher, due to that 'decent' win.