Of notes and coins
Without going into the blame game and details of how we ended up in a situation like this, perhaps it would suffice to say that it is not at all desirable to have too many types of legal tenders of the same value.
Ideally, there should be only one type of currency note and coin for one type of denomination for a reasonable period of time, if not permanently. Too many types for the same denomination tend to create confusion and are also expensive. May be it also reflects on the respectability of the central Bank.
The bank can take the initiative to make permanent/semi-permanent designs for all our currency notes and coins so that with every change of government, currency notes/coins do not change so easily.