Agreed. For example, he strongly advises paying off one's house first. While this is good advice for many/most who struggle to save and invest, it's not optimal

Agreed. For example, he strongly advises paying off one's house first. While this is good advice for many/most who struggle to save and invest, it's not optimal for maximising returns on a given portfolio. If the interest rate is below expected investment returns (minus tax and other subsidies, discounted for volatility), it can often be optimal to invest rather than pay down mortgage debt. It also means more liquidity in the case of sickness and redundancy. Equity in one's home can be difficult to access without some hefty fees or interest rates.