Why they keep changing the release date is because they are translating it. They first translate it, send it to an editor (believe it or not ;^^), and if the editor sees too many translation errors or questionable stuff he has to fix the mistakes etc. Also, sometimes game companies do some more programing and editing on the game (new characters, new weapons, different intros/endings, etc.) which sometimes take a long time to do (sometimes not).
A few other reasons why some games\' release dates are always juggling around maybe because of the system\'s company (Nintendo/Sony) is still checking it out (ratings and such) or the people who are doing box art and promotional stuff needs more time.
Just let everyone work at their own pace. Patience is a virtue you know...