The slow deflation of Bitcoin is not a flaw in any sense, it's additional bonus! If people want Bitcoins, they wil ltrade goods and services for it. Only value of goods and services will determine value of Bitcoins.
IF bitcoin is widely used as currency, even for bank accounts, I doubt there would be deflation.
I don't wanna go into a whole discussion about money supply and money creation again, but a constant monetary base ( = the 21 million coins) doesn't mean there is no (monetary) inflation.
for comparison, USD money supplies:
http://www.shadowstats.com/imgs/sgs-m3.gif?hl=ad&t=1308409874if you look at M1 (which is an even wider defined money supply than monetary base) up until 2008 when everything went to hell in a handbasket, you can see that the money supply of USD central bank money was constant, yet, there was PLENTY of inflation, price and monetary.
same thing can happen in a bitcoin economy.
