Having looked at the stats, I don't think a duel would be that interesting. The Isarimer guy can reroll twice in a duel. Emperor Otto actually beat him the first time! The Lorenvolk guy has a 20% increase in winning the duel, and if he is defeated, he can make a saving roll which allows him to escape unharmed. It'd be a roll fest, but the Isarimer dude has the upper hand on account of being able to fight the duel 3 times. Still, not impossible, and it'd make for an awesome post if Nardoc defeated Lesa. 

If LesaLikl dies though, it tears the Isarimer to pieces. To every advantage, there is always a disadvantage. 

If I were fighting the Isarimer (which I will be in due time, on super hard mode), I would probably ignore their general, or send armies against him headed by a nobody. Cut the strength from under him. Not that I intend to this... at all.