It would be much more than a moderate inconvenience for me.
Personally I think 1 year is insane. 5 or 10 and perhaps thats something which would be reasonable for some cryptocurrency to implement. I wasnt attempting to give the impression that I thought 1 year was a good trade-off. Just trying to point out that the OP's motivation wasn't to take coins from anyone, his definition of sufficient time and notice being crazy is another matter.
For better or worse I think we've already signed the suicide pact on this one. The gut reaction people have is just too violently negative and no amount of reason will get people through it... so even if you could prove that Bitcoin will die without such a fix (and its not clear that this is the case) then you'll only succeed in proving Bitcoin will die.
The first core change is likely the beginning of the end for Bitcoin. There is a social contract. The social contract is a promise to past and future users that things like "transactions are irreversible" will be honored. The VALUE of Bitcoin comes from the contract and the faith users have in it. Stealing coins after the fact violates that contract. If you make an alt-coin which incorporates these ideas from day 1 it is one thing. To do a bait and switch and change the rules after the fact is immoral and it will kill Bitcoin. Luckily there will never be the widespead consensus to make such changes a reality.
As a high preacher of the philosophical school of thou-shall-not-fuxor-the-contract and the view that Bitcoin's existence as a mathmatical object as outside the influence of popular opinion as possible is what makes it worth having, I still do feel the urge to suggest a little caution with the width of your statements here.
Bitcoin in its
exact form, as originally released, was worthless. Anyone could spend anyones coin. Anyone could pick an arbitrary block and slay it so that new nodes would ignore it and split the consensus. Anyone could crash all the nodes (in a dozen different ways). Anyone could create a block 1/32nd the size of the system maximum and cause the system to fragment. Anyone could create unbounded amounts of additional coin. All these flaws and more were in the original software, coded into the rules of the system.
If changing the software, at all, was Bitcoins death then Bitcoin never really existed. ... But clearly it does exist. These things were fixed, in 2010, 2011, 2012, and 2013. I hope that this list never grows, but perhaps it will. Will we put Bitcoin down and walk away because the software is a suicide pact which can never be changed at all. No.
Should our moral responsibility be to uphold the Bitcoin contract? Absolutely. Does that contract include every flaw and mistaken in the software? Clearly not— mankind simply does not have the engineering tools and talent to build it another way. Where is the line? Unclear. Reasonable people can disagree, and thus the taint of the influence of man.
I hope for Bitcoin's sake that serious life or death flaws will remain uncontroversial fixes... and that Bitcoin can survive a few changes here and there, as required, by a true consensus. If it turns out that can't work, I have noting to offer as an alternative: a tyranny of a majority is certainly not what we signed up for.
If that is the case I think it will be truly sad, because I think such a failure of Bitcoin would salt the earth for a generation for the idea of a system whos trust is in math rather than man... but perhaps it will be. Time will tell.
