There's way more at the link, but: http://kotaku.com/why-video-games-are-delayed-so-often-1795473828
Kotaku said:I heard a few explanations for game delays while reporting for my new book on game development, Blood, Sweat, and Pixels. During this process, I spoke to developers whove worked on everything from massive RPGs like Dragon Age: Inquisition to indie platformers like Shovel Knight, asking them lots of questions about why they have to do things like, say, delay their games.
The simplest reason is that, in game development, making an accurate schedule is impossible. Even the most conservative estimates at the beginning of a project cant account for obstacles that will come up along the way. Sometimes a level that a game creator thought might take two weeks actually takes closer to two months. Maybe theyll find out midway through production that their cool new idea for a combat feature isnt fun, forcing them to spend months fine-tuning to make it better. And theres never any way to predict how many bugs will pop up toward the end of development, which is why we so often hear that games are being delayed for polishto catch and fix those bugs. These pitfalls dont just affect first-time developers. Even the most experienced veterans wind up battling time.
When Urquhart and his team first started making Pillars of Eternity in the fall of 2012, they plotted a schedule that would take them to 2014. But they ran into numerous complications during production, including scope issues (the planned game was too big), story issues (their lead writer was caught up on Obsidians other project, South Park: The Stick of Truth, itself delayed for many reasons), and thousands upon thousands of bugs. Eventually, Obsidian bumped Pillars to March 2015.
Game delays can frustrate gamers, but they provide relief for game developers who want to produce a better game, except for the fact that they can extend months of grueling labor. The developers at BioWare had to delay Dragon Age: Inquisition twice. The first delay, from fall 2013 to October 2014, was necessary to expand the games scope and ensure it could have key features like a huge open world and playable races. But the second delay, from October to mid-November 2014, was far harder on the Dragon Age team. That one was to polishto fix the tens of thousands of bugs that had popped up during production. And they were already all working endless days to get Inquisition out the door.
Its awful to have to tell a team that youre delaying for six weeks, said BioWare studio head Aaryn Flynn. Because you know what that means for them is six more weeks of a lot of effort. Its like saying oh, that marathon finish line that we thought was here is actually six miles further, sorry guys.