So for me, the ideal ID system is decentralized, self-declarative, and the weight of the proof depends on the length of history, not on "who" says it's true: there should be many such services where you could declare a name and an address and anything else you wish (phone, email...)
The value after a few weeks would be close to nil, so you could decide to "increase it" by having several people vouch for you (strength in numbers) instead of relying on a "who" (public notary).
Or you could totally decide that you care about your freedom/independence/whatever and NOT ask for any vouching. It may be hard, but after a few years of reliably receiving mail and orders at that address, it would acquire some serious weight - a bit like you tend to trust online accounts that have been open for some year.
Among many other things, this would also allow anyone the opportunity to "change" easily: want a new name/move to a new address/etc: create a revocation certificate for the old, sign it with the new, boom you inherit the credential history!
It's just a quick idea, but it shows how IDs could be more like URLs (multiple competing services, and you could have a few at the same time, why not!) by moving away from the current system that's a direct descendant of the census (give the lord a list of people to tax them) and the passport (limit freedom of movement during the war)
At the core, I believe people should be in control of their identity, not governments or states.