But whatever McKiernan's shortcomings, the quality of military leadership pales by comparison to the other shortfalls in the administration's strategy: a common approach with the Karzai government to the use of military force; inadequate vision and resourcing for the essential non-military tools (diplomats and judicial advisors and agricultural experts and economists); and an unrealistic timeline on which Afghan political leaders, soldiers, and police can provide for themselves. A new military commander cannot solve these problems, and the Afghanistan war cannot be won without solving them.
The danger for the administration in having relieved McKiernan will come if their Afghanistan strategy does not produce the desired results on the expedited timeline the administration has committed itself to. McKiernan is on record as having asked for at least 10,000 more troops than the administration provided, and given his military judgment that the political objectives military force has been enlisted to help achieve would take a decade. If Afghanistan does not turn, the Obama administration will have just created this war's Eric Shinseki.
Also, here is the link to an article about then-LTG McKiernan's role in the invasion of Iraq:
Dash to Baghdad Left Top U.S. Generals Divided