Reality is that IF you are going to have laws of use and restriction of ANYTHING, and you don't have the ability to instantly check a person's statis in this regard, then a permit/license system is nessisary. That was a major motivator for drivers licensing and firearms licensing (yes, there were/are other factors for the adoption of both). This is not support or opposition to either, just a statement of reality and history. For firearms licensing, one of those "other" factors was/is control and/or racism through discretion/suitability.
BUT, the major motivator of adherence to the law fails as a licensing requirement once you have the ability to near-instantly check a person's status. Of course this brings up the question of when is a status check allowable. Is it only with probable cause, reasonable suspicion, mere possession, or only during a transfer/transaction (this would run the risk of becoming a registration database)?
I don't think restrictions on 2a will ever completely go away. Even with the very valid argument that if a person is safe enough to walk freely in society then they are safe enough to possess a gun, I just don't think this will ever become reality. And we have to live in the real world.
So would I support state licensing, yes but only under very strict conditions. First is it cannot exceed any Fed restrictions, it's free to have less, but not more. It absolutely must be shall issue and must be done so in a timely manner and easily accessible place. And it must, absolutely stand in for any purchase based background check. It cannot have any discretion and must have reciprocity with all other states. I doubt this would ever happen.
On the other hand, having an instant background check, NOT THE WAY IT IS TODAY, might be a viable alternative IF we are staying with the idea that there will be 2a restriction. It would have to be near-instant and eliminate any waiting period, they need to fix the appeal process, and there needs to be real accountability of those that report data to the system for any mistakes. The default on a "no response" has to be approval. It would have to be limited to new purchases at dealers for a number of reasons. First is just practicality, exposing the systgem to just anyone is a recipy for disaster. And second, is that expecting the average Joe to maintain accuracy and integrity of the process is a fantasy.
In the end, COULD either system work, possibly, but WOULD it work, probably not given reality.
Will I get flamed for trying to take a real world look at the the situation (even though I've offered no definitive opinion), DEFINITELY.