Firstly Froch has a very good jab, he has long reach and throwing it from a low position helps to catch opponents off guard. His boxing skills are very underrated too, many technically superior opponents have unravelled against him and not respecting his ability has contributed to that. That being said, his main attributes are his outstanding conditioning, chin and mentality. Froch can psychologically break fighters down by taking everything they have and then being relentless with his own onslaught, he can work for the full 12 rounds at high pace and gets stronger has the fight progresses. Carl Froch is the definition of a 15 round fighter.
Pretty much sums up Carl Froch. Maidana and Salido are kind of like this too. They look crude on tape but are very effective.
Not enough conditioning is obviously a problem, but too much and you sacrifice speed and power. There's a happy medium for boxers and it's certainly not the difference between winning and losing. Guys often said to have 'bad stamina' are guys who fight all out (Taylor, Haye etc.) rather than pace themselves, and guys said to have 'good stamina' are often guys who throw pitty pat punches or pace themselves well (Calzaghe, Floyd etc.). It's about intensity and pacing when it comes to lasting a fight, no one in the sport is exceptionally conditioned. It's just not that sort of a sport.
Hahah, of course I did. What relevance does "who would you rather go to war with" have here? I'll humor you and say you were discussing 2 man tag team boxing matches instead of literal warfare (equally stupid to bring up, but whatever). If the weights of the opponents are equal to those discussed, I'll go with Mayweather. We've seen Froch go to war and lose.
He does have an ugly style and a ton of flaws. I had high hopes for him when he turned pro but I never saw the improvements in technique that made me believe he would ever be a world champion. But then he proved me wrong, for all his flaws he has an indomitable will and self belief. Many think he is arrogant and in a way he is, because he has tremendous self belief bordering upon irrational and that sheer refusal to quit even for a moment makes him very dangerous. Even when he was dropped by Groves and taking bomb after bomb I doubt he ever for one second thought he would lose. But he isn't just will over skill. He has a good jab and very long arms. He surprises guys with his reach, catching them with shots when they think they are out of reach. He also throws unexpected shots from sometimes unexpected angles. He hits hard, not a devastating puncher but the kind that will wear you down over the course of 12 rounds and if he lands cleanly like in the Groves rematch can take you out. He is always in shape and is just as relentless in the last round as he is in the first, he threw almost 1000 punches in the rematch with Kessler. If you can't KO a man and he throws that many punches with thudding power it makes him hard to beat.
Soley because he has an iron chin, without it he'd not have got to world lvl and a huge fan but its pretty clear