You were basically making out that nothing that the registrar could do would allow them to recover the name and verify the person - so are the current registrant details usable or not for recovery of the domain?
Many registrars do make good faith efforts to try to sort these things out. Yes, the details are important - as are things that are not so obvious like historical access logs and patterns, other activity in the registrant's account, other activity in the transferee's account, and so on. That's why a lot of stolen names get sorted out on an informal basis without legal action of any kind, as
@bhartzer will attest.
So, sure, a lot of these do get sorted out through the application of common sense and existing data.
But here, you have a registrant that is a corporation. Corporations have lives which are separate from their owners. This can be helpful in some circumstances and not so helpful in other circumstances.
It's worth pointing out that, other than the specialty corporate registrars like Safenames, Markmonitor, CSC and so on, ordinary retail registrars do not do a good job of distinguishing between "a domain name registered by an individual" and "a domain name registered by a corporation".
In fact, in ICANN policy discussions, GoDaddy objected to a proposal that registrars expressly require registrants to state whether the domain name is owned by an individual human, or by a business entity of some kind.
That ambiguity causes huge issues, and was a major headache in running, for example, a domain marketplace. Somebody buys a domain name for their employer, and their employment ends prior to the domain transfer or payment plan being completed. Was the buyer that individual, or was the buyer the company?
The Nissan situation is the worst combination of facts. You have a domain name owned by a company. You don't know who might or might not be all of the shareholders of the company in relation to the person who was the authorized contact, but the authorized contact is now deceased. So, you have the estate saying the domain name belongs to them, but to whom does the company actually belong, since it may not have been 100% owned by the person who was the authorized contact.
The guys who run gkg.net - which is not the most sophisticated registrar on earth - have a lot of battle scars they've accumulated over the years, but they also have the good sense not to wade in as judge, jury, and executioner with a domain name that has been the subject of prolonged legal disputes over the years. They are unlikely to get involved in deciding who is the "rightful owner" of a domain name that has been fought over for ages.
Personally, there are some things that I've never quite understood about Uzi Nissan making that litigation the central focus of his life, never seeing a dime from it, and leaving it a mess for his estate to clean up. They now have the privilege of spending money to recover it, unless there is a contingent fee arrangement of some kind. But, if there IS a contingent fee arrangement of some kind, then the simplest route is to simply sell the car company the right to recover the domain name. Although, there may be an underlying arrangement of some kind through which this piece of litigation is being conducted. Whatever the actual underlying arrangement might be, it goes without saying that obtaining a court-ordered transfer of the domain name to its rightful owner provides an unassailable title to it.