Should a world Champion make a defence against.....

Knowing how lazy Bowe was, I probably would have tried to make it second after one easy money defense. Bowe certainly would have kept himself somewhat sharp knowing he had Lewis has his second defense or as a reunification fight.
Newman probably cared a lot less about legacy and more about money.

Ferguson was actually a decent fighter when he was younger and more a victum of bad management and being rushed. He has a win over an experienced James Douglas with only 10-11 fights under him.