You don't think Switzerland, Denmark, or Japan have reasonable central banks?
Denmark just follows the ECB so they have close to zero intellectual liberty. Switzerland is a special case with its safe haven currency and a few quirks. That leaves ECB and Japan.
Japan I don't know much about, so won't comment on that one.
As for the ECB, you have to remember what the goal of the central bank is: To get inflation to around 2%. It has not been there for ages so they do what they can, within their mandade, to try and get it there. There has been increased mumbling about the lack of the interest rate as a functioning tool when monetary rate is already this low (it not like -0.25% or -0.5% has a meaningful effect on your will to borrow to invest in sth). And negative rates are a massive tax on the banking system in the Euro-zone, curbing bank profitability and in turn bank's ability to lend money. And with low rates people are, much to the surprise of the ECB, increasing savings due to lower future expected returns. Then you have the effect of the low rates on the sustainability of various pension schemes around in Europe.
I am 95% certain that when someone does the tally in this monetary experiment at some point in the future it will be deemed a major policy mistake with adverse side effects, inflating asset prices instead of generating productive economic acticity etc. One thing is having low interest rates, but when you make them negative weir shit starts happening and those effects are getting attention now.
Tiering at the ECB has already been introduced - without going into details it means that banks in the Eurozone can deposit a good chunk (in some cases probably all) of its surplus cash in the ECB at 0% instead of at the target rate (-0.50%)
