Field Hunting Trials (Medium size game)
Advantages:  This would retain the true character of the Jindo in the face of show and guard breeding pressure and tendencies.
Disadvantages:  According to a 1994 article by Kim Chung-ho in Koreana, a bizarre hunting law in Korea states that hunting with purebred Jindo dogs is illegal. I don't know if this law has been amended in 1998.  It would take some organizing by experienced general and Jindo hunters to design a trial that would be easily set up and yet discriminate between the average but capable Jindos from the really good hunting Jindos.  (Previous attempts have included releasing rabbit in a pen...naturally all the Jindos caught their rabbits in such an enclosed environment.) Jindos usually work independently of human direction and apparently silently when hunting so the baying trials utilized by hunting hounds in the US would not apply.  Humane treatment of the prey would need to be considered in the US.

Bird Hunting Trials
Advantages:  Apparently, there has already been success in teaching Jindos to retrieve fowl and pheasant.  Easier to teach and train a Jindo with the easier access to birds.  Not as much outcry in regards to humane treatment of birds. Would allow the Jindo to adapt to the changing world without losing too much hunting ability.
Disadvantages:  Training a dog to always be "birdy" even in the face of mammalian prey.  Jindo would need to learn to work closer to his/her handler.   Development of the soft mouth.

Herding Trials?
Disadvantage:  It's not really certain if Jindos originate from the herding dogs of the Mongol invasions. Don't know if it's possible to convert the Jindo's present instinct to hunt and kill into herding.

Catch Dog Competitions
Advantages:  Still politically acceptable as hogs are considered a dangerous pest in many parts of the country.  Associations are already in place that offer these competitions.
Disadvantages:  Jindos are not catchdogs or gripping dogs.  They attack hogs/boars with the intention of killing and maiming, using various methods to do so.   Sometimes that involves harrying for hours, which is not desired when humans are involved in the hunt.  There is too much risk that the hog/boar will turn on the people.

Tracking
Advantages:  Jindos in Korea are utilized by police and military for tracking.  Obedience schools in the US offer a version of this.  Non-violent.  A person can train at home.  Further application to search & rescue or drug sniffing.
Disadvantages:  By itself, tracking does not necessarily equate to intelligence or physical ability.

Lure coursing:
Advantages:  Allows the Jindo to have a good run and stay in physical shape.  Non-violent form of chasing prey.
Disadvantages:  Intelligent dog breeds like the Basenji tend to either nail the lure (plastic bag) by waiting at the wire or just simply don't care for it after the first couple of runs.  A Jindo isn't a sighthound.  Intelligence isn't selected for in this sport.  Requires some work at setting up the course.

Agility
Advantages:  Extremely fun for the dog (well, usually...) .  Increases the dog-owner bond. Keeps Jindos agile and trainability is selected for.
Disadvantage:  Recalls should be reliable.  Jumping can start only after the dog is physically matured.  Tendency to collect agility equipment at home.

Obedience/Utility
Advantages:  The ultimate test of trainability of the dog.
Disadvantages:  Only at the very advance levels does intelligence and sound temperment play more of a factor than trainability.  At the lower levels, sometimes a poor, unstable, temperment can be hidden by training.

Schutzhund
Advantages:  Tracking test, obedience test, and protection (courage) test all in one package.
Disadvantages: Coverting the Jindo's defensive drive (warning growl/bite in response to an agitator) into an offensive drive (chase down, bite hard, and don't let go even when person is fighting back).  Dogs bred for and suited for this work have harder temperaments (more imprevious to corrections) and are unsuitable for the average pet home.  Takes a lifetime of continuous training once the dog has learned to bite offensively.  Some dogs have low prey drive towards inanimate objects and so imprinting onto a sleeve is difficult.

AKC Canine Good Citizen Certificate
Advantages:  Any dog can test for the CGC.  The certificate can be used as proof that dogs are not a danger (keep home insurance).
Disadvantage:  A bit of training is involved.

American Temperament Test Society Certificate
Advantages:  Test is geared towards testing recovery to stimuli rather than testing trainability.  An untrained dog can participate and pass this test as long as he or she is temperamentally stable.
Disadvantages:  People will sometimes train dogs before the test so intepretation of results can be skewed a bit.