While Gettysburg is a grand drama, full of sturm und drang and derring do, in any strategic sense it pales in comparison to Vicksburg.
While Lee was brilliant tactically, he was devoid of strategic sense. He had the capacity to make the war long and bloody but no realistic chance of winning.As each day passed after Chancellorsville the CSA got weaker and the Union got stronger.
In functional terms the worse enemies of the South were RE Lee and John Wilkes Booth. Lee because of his tactical brilliance but strategic blindness and Booth becasue he killed the only man standing between The South and A Brutual Reconstruction scheme.
According to Mr. Longstreet, whom admired Lee a great deal, Lee though brilliant was too expensive for the south. The south could not afford the costly victories which Lee achieved.
I agree, Vicksburg was by far a greater loss to the south.
My judgment of Lee's military record is almost exactly the opposite: that he was strategically brilliant and too aggressive, tactically. He knew that it would take a major victory on northern soil to create the conditions for southern independence.
Where I think Lee can be criticized is for his tactical handling of his Army -- he nearly always assumed the tactical offensive -- and so nearly always lost more troops than he could afford. To be fair, there wasn't a good tactical solution available in the 1860's to negate the casualty-producting technology of the rifled-musket.