It wouldn't ruin the deflationary system. The money supply hasn't changed, there will never be more than 21M BTC. Nobody says purchasing power can't decline even in a deflaitonary system. Gold prices for example have both risen and fallen over large periods of time.
As far as random people getting a large number of coins well that has already happened. They are called early adopters. The system doesn't care, the initial distribution is just that INTIIAL. Unless people want to die poor with lots of coins they will spend them on goods and services creating a secondary distribution.
You make a good point. Thank you for the constructive post. It has definitely made an effect on my view on the matter, in a positive way.