Delays are common place within the video game industry. Historically they carry a stigma with their occurrence. The consumer is apt to assume the worse when a delay is announced for a title. The assumption being that it means the developers are having difficulty getting the game to work properly, there are financial troubles, or the game is headed to be cancelled. But over the years, delays have begun to mean much more than that.
In the rarest of moments, a game may receive a short delay, usually consisting of a few weeks to a couple of months. This is usually done from a development side. Made so that they have more time to polish up or to refine last moments and avoid putting out patches. A studio would really want to avoid patches as they can be quite cost assuming and are usually restricted in allowed size for bandwidth reasons. More often it is the publisher who causes the change of any length these days to coincide with some financial plan.
It has become common place for multiplayer to be shoe horned into what are traditionally single player experiences. Many publishers do this as it is an effort to increase sales base and open avenues for downloadable content. The difficulty with this is that single player experiences often suffer. While most is considered rumor and hearsay, occasionally there seems to be evidence of this occurring to the player.
Sometimes a publisher wants to create a delay so they can introduce something else designed to make them money. They may push back a release to allow for an early access program to exit beta status and work to get more subscribers. They are aware of the desire for the titles they are pushing out and work to get a few dollars more from the consumer by releasing a piece of a game that is possibly finished through their service.
The delays that span 5 months or more are the ones to still be wary of as it concerns the actual development at that point. Optimistically it means the addition of much more content, but realistically it means that there is issue with getting the game to work properly and it may need many aspects rebuilt just to be properly playable. In the end though, anything viewed in regards to a delay is colored by the consumer. Publishers and developers need delays to keep the business viable, but the delay reasons should be properly communicated. The consumer can see the benefits of delays when a game comes out, and no one is more vicious to sales and reviews when a game comes out before it was ready.