List of current Warhammer 40,000 Codex by release date:
6th Edition (2012)
Chaos Space Marines: September 2012
5th Edition (2008)
Necrons November: 2011 (Made with 6th in mind.)
Sisters of Battle: August/September 2011 (Made with 6th in mind.)
Grey Knights April: 2011 (Made with 6th in mind.)
Dark Eldar November: 2010
Blood Angels April: 2010
Tyranids January: 2010
Space Wolves October: 2009
Imperial Guard: May 2009
Space Marines: October 2008
4th Edition (2004)
Chaos Daemons: May 2008 (Made with 5th in mind.)
Orks: January 2008 (Made with 5th in mind.)
Chaos Space Marines: September 2007 (Made with 5th in mind?)
Dark Angels: March 2007
Eldar: November 2006
Tau Empire: March 2006
Black Templars: November 2005
At only 4 years and 1.5 editions old (1.5 because it was made for 5th as it were), and considering it still has numerous viable builds (as well as new units added) it's far from being in dire need.
Black Templars and Tau
deserve it next, and Dark Eldar had to wait 12 years ( Codex released 1998, minor update, basically including the
FAQ and 2? variant units in 2003. ) so 4 years is nothing, and certainly way too early to start claiming 'will they ever.'