Froch would rank pretty high on the list. Having said that, I am a BIG fan of Froch....but even *I* realise that he is a guy who is running more on heart and determination than innate talent. But that is a COMPLIMENT to him. Anyone can be great if they have a gift at birth, and simply go through the motions, taking advantage of their GIFT. I have much more respect for a guy who triumphs through HEART than simple genetics.
Froch isn't talented in terms of skills, but he is very strong and he has above average power, stamina and a hard chin. I'd say he has plenty of physical talents; even in terms of skills, you have to have some skill to be that slow and win decisions at a world level. Like you say, it's his determination that makes the difference. I don't think he's very naturally talented, but he trains very, very hard; he has plenty of experience; and he's reached his 30s which is when most boxers reach their peak strength.
Douglas KOed Tyson. At least he earned his title. The WBF have got some absolute doozie titleholders.