This is where I disagree with you. Keen says exactly the opposite in regards to the need for a central bank. Drastically so in fact. His proposal for the current crisis is a 'debt jubilee' funded from central bank created money - effectively creating money and giving it direct to debters instead of using QE. His opposition to neoclassical notions of exogenous money is that it leads to the belief that QE can solve the problem of liquidity, when his own models show this strategy to be inferior to direct giving of money to firms that are in debt.