Hey, I know this is probably was considered before, but why not make coins have limited age before they return to coinbase? Say if coins have not been moved for 8 years it "returns" to coinbase (i.e. become unspent) and become minable. This way coins that was unspent for certain amount of time will eventually reenter circulation, we can discontinue block reward halving practice, eliminate satoshi's stash (or force him to reveal himself) and reintroduce destroyed funds to the market. This will also limit blockchain size so we would be able to use much larger blocks, allowing much more tx/second since blockchain size will be capped. More I think of it, better it seems from scaling perspective.
I know I probably missing some significant downsides but I can't see something that can't be compensated.
You have made a valid point in that in this current situation that bitcoin has found itself, there is need for serious thinking out of the box in making the situation a better place. However, the suggestion you made from where I stand, are not improvement rather they are complete deviation or alteration of the initial plan.
On the issue of returning coins to coinbase or any place at all, that is centralization which is making some body have direct influence over the entire bitcoin. The number of years you suggested is another thing because with the potential that bitcoin has, some people would keep beyond 8 years who should then repay them in case they come back for their bitcoin.
Other ways should be suggested on improving the current situation but not this.