I thought about this before. Issue with the FOID is instead of registering the firearm, you're now registering the person. And you can't have firearms without the FOID. So if a person just has one gun for their lifetime, they have to continue to get FOIDs while they own their gun.
Filling out forms is a PITA and could be more efficient.
The obvious breakdown in the current system is a person could have already purchased a number of guns under individual pistol and long gun permits. Then suppose they become addicted to meth, have an untreated mental health problem, etc.
That person has no need to go out and buy another gun should they be planning on creating havoc. They are already in possession of firearms.
Without a mechanism to update their status with regards to being a safe, responsible gun owner, they will fly beneath the radar until they get caught doing something illegal. At that point, you're locking the barn door after the cows have gotten out.
If they "register the person," as you said, then there would be a background check and review of medical records periodically assuming the person wants to continue owning guns. As it stands, that doesn't happen in HI without the submission of another permit application.
RAPBACK was supposed to fill this void, as sort of a running background check system. Anything that's reported to the system regardless of the state it happened in is updated in RAPBACK, and HPD is notified. HPD can then decide if a review of the individual's fitness to own guns needs to take place.
Of course, RAPBACK has never been implemented for gun owners as far as I have seen, but it does focus on a potential solution for the permit problem -- identify adverse changes more often than "whenever they buy another gun -- if ever."
I think an FOID would be a good compromise between total 2A freedom and what we have now. Walk into a gun shop with a current FOID, and leave with whatever you want to buy -- no wait period required.
That's the other stupid thing. Why enforce a 2 week waiting period for someone who already owns firearms? Is that newly acquired gun the one we ought to care about as opposed the 30 he already has at home?