Hi Remi, thanks for writing this piece. It accurately describes the problem that we at Dusk Network have been working on solving. Dusk Network falls into the third category that you describe and is a blockchain purely focussed on enabling compliant issuance and trading of digital shares. This mean that we are building a whole new blockchain infrastructure that is completely anonymous (where it needs to be) and has built in on-chain compliance tools to deal with all regulatory compliance requirements. E.g. of functionalities: transacting is only possible to whitelisted individuals (who have successfully passed KYC/AML with the issuer, or with a third-party that the issuer has approved), full anonymous transacting of the XST token on the outside, while the issuer can decrypt the ownership data and use that to power cap tables (automate reporting and more). You mentioned that category-3 solutions are years out, well.. we have good news for you. It will be a few more months until we release our main-net!
Furthermore, we are positioning ourselves as a decentralized protocol, and we will allow anyone, from anywhere in the world, to create XST tokens at the same price as it now takes to create ERC-20s on Ethereum. We do not gatekeep our technology, and we welcome any category 1 and 2 solution to build onto Dusk. Mind you, we are not competition to them, by providing an on-chain solution we will be able to help and benefit Token Issuance Platforms, whom currently need to deal with counterparty risk (from maintaining off-chain registrars).