The 'underwriter' in dharma protocol is essentially current day middleman. You contradicted yourself by saying "trustlessly" in point 1 and then admitting to point 3. Point 2 is unenforceable without current legal system.
Underwriting is a heavily regulated process in most countries with licensing requirements. You could claim that you do not underwrite yourself,so don't fall under regulatory purview. Interestingly your model will fall under the P2P regulations of India and China - where there are specific models where the marketplace does not underwrite, but risk is assumed by lender. Or - you have to make sure that the underwriters are regulated entities.
P.S. I run a lending startup in India. We primarily look at the Blockchain as a means to solve the credit history problem in India.