We all want shielded usage to increase. And transparent transactions are a philosophical contradiction for Zcash. Remember, you can always disclose the contents of a private transaction, even on chain. Just the default is private. There is a use for transparency on zcash , but there is no long term use for Bitcoin style transparent tx’s which are public by default. Defaults matter and as a protocol, Zcash doesn’t have privacy by default until they are gone.
We can’t force shielded adoption by getting rid of transparent transactions, and we should be aware of the risks of getting rid of transparent transactions too quickly. But we can still create market incentives to make exchanges support private transactions and make users demand it.
With that I have a proposal: we cap the amount of block space that can be used for t2t transactions ( and then later t2z). We set this cap at say 105% of current transparent usage. Optionally, we can have a soft overrun allowed, but at sharply increasing prices. And then we have the available amount halve with each halving.
This would give everyone, exchanges and wallets included, predictable steady pressure towards removing public transactions. As fees go up, exchanges will want to use shielded to reduce the fees they pay. If they pass them on to users, users will demand they support shielded.
Zcash is remarkably scalable even right now. 2mb blocks every 75 seconds gives it about 7 times as much block space as Bitcoin. Why should any of that go to bitcoin like transactions?
I wanted to use this thread to see if 1) this is a good idea 2) how big the overrun allowed should be 3) discuss what the pricing mechanism should be for extra transparent transactions in the overrun (maybe theres an EIP 1559 like scheme if @vbuterin thinks about it ). Maybe we should just have the price increase for every subsequent transparent TX in a block.