The Ardent is included because it is PHB3 preview material. Preview material is usually included in the Character Builder update for that same month.
The Artificer build is Dragon material. It is not preview material. Because it was part of the November issue of Dragon, you can expect to see it in the January Character Builder update. This is true of all Dragon material, and here's why:
When material is first published in Dragon (or Dungeon), it isn't necessarily in its final form. The full issue of the digital magazine isn't compiled until the end of the month, after all of the material has been released, and up until that final compilation comes out at the end of the month, the material may continue to be revised. Because of this, the true "final" version of Dragon material isn't released until the end of any given month. The D&D Insider tools team then needs time after that final version is released to prepare it for the Character Builder, so it ends up being released a little over a month later when the Character Builder updates. In essence, there is a two-month gap between material being first published online in Dragon or Dungeon and that material appearing in the Character Builder/Adventure Tools/Compendium.