People will get mad.. but it doesn't take long for them to get glad! I think the forums are a way to let out Real life frustrations without actually saying the problems.
I rather people get mad at waiting for a long time and say hey this game is awesome at launch, than releasing a buggy game early and saying, SE THIS GAME SUCKS, blah blah.
I mean SE could release a "Time frame" for the release. but that is only if they can meet that timeline. However, it's hard to make a "exact date" until they are close to releasing it.