It is still unknown what their long-term effects will be (e.g. on the erosion of bank profitability). In contrast, QE has been tested successfully in the US and the UK and I would also like to remind you that monetary policy– conventional or unconventional – entails considerable time lags. It takes time to see the results at full length.
It is therefore important, despite all of the well-reasoned criticism, to be realistic. All too often, the proportionality debate is used to wrap general criticism of regulation in politically correct packaging. But this criticism clearly goes too far on three accounts.