I understand the "damned if you do, damned if you don't" argument relating to speed of release vs. stability of code but this is different than most other release situations.
Unlike most moronic devs/publishers who announce the game 5 years ahead of time, HL2 was developed in total secrecy; there was no pressure of a release. They had the financial backing they needed, they had a gauranteed seller being the sequel to HL. They had total freedom to pick any date. So when they at long last came forward and said 30 Sep. it was naturally assumed by most that this would much firmer than the average release date.
I'm sure the game will be good and I'm not going to lose too much sleep over this but speaking strictly about the date issue, Valve/Vivendi deserve to get called on this one.