Delays? Oh no! Delays were rife through the entire 7th generation as well, and the 6th generation. Heck, the Wii U had a bunch of delays in 2013. This is nothing out of the ordinary, especially for a huge production like Destiny.
It could be a somewhat tactical decision by the publisher, moving the game closer to fall would yield more sales, or it could te technical issues, adding more content/features/support.
Games are delayed all the time, what does it mean? That the game won't arrive at the original date set.
"Place-holder" is a terrific word to look up, initial release date postings are often place-holder dates.
Edit; I'd like to clarify something. I imagine John Lucas is going to attempt to turn my "market branches" or "breadth" and the overall expansion of the gaming industry into an "imminent video game crash" argument. There were between 8-10 home consoles on the North American market alone, home consoles being all the rage, everyone wanted a piece of the cake, much like the influx of shit mobile phones we had in the mid 90's. This is not in any way comparable to today's situation, unless you want to really, really reach for straws and claim that developing markets around the world purchasing previous generation hardware far into a new console cycle somehow constitutes the market being flooded with home consoles. The lack of publisher control is nowhere near the catastrophic early 80's either, not even close. One can imagine console manufacturers being desperate for software with so many machines competing for the same market and audience, they would pretty much accept anything, there is no such strain on the home consoles of today.
It is my belief that the very fact that the market has branched out and is effectively partitioned the way it is, is what is going ensure that another video game crash will not happen. Nor is there any cause for thinking that all developers would suddenly wind up in a shit storm, there was a similar debate in the 90's with the jump into VGA and SVGA rendering, economic troubles lay ahead for some due to increased budgets and the market was a lot smaller then, making it harder to offset production cost. They did just fine, this spawned procedural generation and other nifty developer tricks and ended up being a huge boon in the long run and also turned focus onto optimization for specific chipsets (i.e; part of what caused console games to look and run as terrific as they did ever since, relative to their hardware specs) to maximize programming output and gain.
The "HD-scare" of the 7th generation is another transition in developer history and has forced smarter solutions (outsourced engine and developer tools being a huge one, as mentioned eariler) and has made investor faith more hard to gain or retain(the primary reason why some companies shut down after a single failure on the market and also a form of publisher control, self-regulation through qualifiers in the corporate structure, unheard of in the 80's industry), and all this has also occurred (as mentioned) in the middle of a financial crisis that you have to go back to the 1929-1935 period to match. The fact that the industry has even made it under these conditions, with entire nations going bankrupt, speaks volumes of their ability to survive.
