This. It is likely that an anniversary event brings more players - lost and new ones - to the table than just any game update throughout the year, and anniversaries get easier attention in gaming news. Each anniversary is a game's opportunity to shine and to reel in more players, so the idea of doing an Apple-inspired kind of announcement here is not too far fetched (keep silence until the actual launch). Also consider the fact that the team has spent a considerable amount of working hours on making the new crafting system. The timing of the launch is crucial in order for the company to achieve the highest financial gain possible.
Another thing: Over on the testlive forums you can see people requesting for the crafting update not to hit the testlive server. Why? Because it will give testers an unfair advantage, getting to know (parts) of the crafting system before the rest of the players. An example: Stone type X is in heavy demand in-game right now, but with the crafting update, this type of stone will no longer be in the game. What happens? Those who know this, will rush off to the traders and sell all their type X stone and reel in tons of money before the crafting system hits the servers. Another example: testers will get the (unfair) advantage of knowing what kind of material combinations will make the best crafted items, and then be able to produce these already on day one after the update has hit the live servers.