No, they didn't rush the game. Diablo II has been out for more than twelve years and it's still buggy, despite frequent patches.
If a game's release date is pushed back every time a new bug is found, no games would ever be released.
what I'm saying is that when you give a hard date almost a year out you WILL rush things when it gets closer. You WILL miss things when it gets closer. Why? Because you have painted yourself in a corner with the hard date.
They should have waited and gave a hard date when the game was closer. This way there would be no rushing and if you had to push back the date you can.
I never liked the hard date when it was announced, and I still don't. I see the results of that in the Day 1 patch and then another pach to fix the graphics problems.