The problem with doing it in phased wise manner would have meant that those with black money would have got chance to find out ways to salvage it. Already people are doing/done things to bring down loss. Brains of our people run too fast and in too maverick ways on such matters
There is also the point of people panicking and queuing outside bank from day 1 when there are close to 2 months to do so. It is understandable for poor who don't use card much and want to exchange the big denomination notes soon but even middle class people are doing so who can get most of things done using card.
Saw couple of messages yesterday from people on FB that they went for exchange and got it done in 15 min flat. Not in a village, in a big city so even the long queue thing was just for a day or two. It is funny when some people suddenly see standing in queue once for a move which can eradicate the biggest problem of country a large inconvenience. Standing in queue for hours and hours at religious places, waiting for an hour outside restaurant, waiting for hours outside idiotic movie stars' house to catch their glimpse is something they are fine with. Thankfully, the majority of opinion is that it is a good move. PM in his address himself had said that this move will definitely cause 'some inconvenience' and requested people to bear with it with for long term objective.