Macro cycles have no concrete evidence of it being powerful or otherwise!!
Theres an amount of wishful thinking and perspective and even searching for facts to fit the model, but nothing we can say that is 'firm'
And why are mystics required to believe in a specific date?
Nostrodamus used the 'tool' of the mystics(and most likely the instruction booklet) and he said humanity would continue well after 2012. In some quatrains it suggests an interstellar route for man. The planet configurations where merely 'time' markers for him, thats why he used them to mark out significant events, because they are all our calenders.