Proof-of-work has a bunch of issues surrounding electricity usage, transaction scalability, and latency. It's not acceptable for a commonly-used currency to take 11 minutes to confirm transactions, nor is it acceptable for it to use more electricity than Ireland to do so. There's a bunch of research on fixing this, from various proof-of-stake systems to new consensus protocols to Nano's precomputed proof-of-work to Iota's tangle. But none of them have the track record that Bitcoin does, nor do we know if they're secure under concerted attack, nor do we know whether they'll lead to eventual centralization of power and the ability of a few actors to rewrite the ledger. I'd like to see more experimentation in this space and some actual usage with special-purpose applications before it gets rolled out by fiat across the world.
The other thing I'd really like to see is automated central banking. I don't buy the "you never need a central bank; let's just have a deflationary currency!" arguments, but at the same time central banks have a lot of problems with measurement, fairness, and incentives. I'd love to see the whole institution replaced by a computer that automatically maintains stable prices by giving money to everyone to expand the money supply and sucking it out (taxation?) to contract it, which was Milton Friedman's original idea when he came up with monetarism. To my knowledge nobody's really building this, though, and it requires solving some thorny problems in how exactly you measure price levels.
I think this could work, if all are taxed then all will feel more equal, the system could maybe funnel a little more $$ at the lower echelons of society than the upper's -- maybe have it simply raise networth's to some arbitrary minimum... make sure everyone has at least 1k in the bank at all times for instance to cover rent regardless of socio-economic factors.
We'd need to do away w/ cash though, or people could game the system by just withdrawing it all to appear 'poor'.
If you want to pay people a basic income, then lets pay people a basic income. No need to sneak than in via the money we are using.
And why force shops to accept any currency? If anything, legal tender laws should be abolished.
(Though in practice, they don't have much bite most of the time, because the shop can just set the official dollar price for a banana at 1 Million USD, and give you a 'discount' if you pay in their preferred currency, be that Euro or Cowrie shells etc.)
FDIC was also a mistake, but let's not get there just now.
It would need some centralization to ensure gamers don't double dip and get 2x benefits from the dole.
There have been a gazillion discussions on how to ensure single identity in a coin that has basic income baked into it, and as far as I can tell nobody has a good solution, some web of trust protocols are promising but still way early in being useful.
I think the only way GBI will ever work though is via some sort of crypto, waiting for the governments to enact anything will probably fail, and crypto being electronic it drives cost down even more (no printing of checks required - all automated).