Hi, I don’t have a Medium account but I read the TL;DR and the proposed picture at the bottom.
Removing Web3 from the dApp and adding a specific vendor… I think this is moving backwards. We should encourage the visitor (and the browser on their behalf) to have web3 services available. Just like we depend on them to have XMLHttpRequest available.
You are proposing MetaMask to make changes. This is fun but it wont happen. MetaMask /still/ doesn’t support ERC-721, a large application class on the blockchain. And right now the way the ecosystem works is that everybody wants to reinvent the wheel. Just look at the number of ERCs created. That paper proposes adding a 2+ year delay for the user interface to update every time somebody wants to update a new application.
2a. One solution is to make the creation of the Signer UI customizable. As in you can design new forms (they can be responsive) and layout the elements on the page. Boom, then you just reinvented what we have today.
But don’t let me stop you! I think all this is good ideas, and I’d love to see you try. But the most likely way to make this reality is for you to fork MetaMask and implement this stuff. If your vision requires you wait for other people to implement this stuff then that is unlikely to ever happen.