How is that abuse? If they want to get their chars killed, let them...
I can live with duels till surrender disappearing, but I feel that over the years too many restrictions have been made to avoid abuse while in my experience abuse was really not running rampant. And well... I don't like that parts of the game that are enjoyed by many need to be completely removed because of some bad apples.
In this particular case: I had an idea all worked out where duel till surrender would be used to fight over a hugely prestigious position. It can be done with training matches, but training match doesn't sound quite as grave or fitting as duel till surrender. Especially as if you lost, you'd actually have to surrender your position.
Of course this is just one - rare - use for the feature, and it is not even absolutely necessary, but it really sucks that duel till surrender might be removed because of the hint of abuse and I don't think you should take removing a feature lightly. Sometimes the good outweighs the bad.