I'll play devils advocate here and I'd like any opinions on the matter. Could Ewell be framed as a great commander on par with Jackson or Longstreet? @NedBaldwin notes many of his accomplishments in the Valley campaign. We have discussed his service at Gettysburg and the Wilderness.My opinion has been- and remains- that Ewell was "a competent commander", but not a great commander. He most certainly does not belong in the company of Longstreet and Jackson.
When considering his performance at Gettysburg, it is important to remember that Lee was ultimately responsible for the defeat.
Added to the above most importantly and overlooked are his actions at the Battle of Chaffin's Farm that prevented the fall of Richmond in Sept, 64.
Pfanz: "Ewell personally regarded the battle of Fort Harrison as his greatest accomplishment of the war, contending that 'it was in the enemy's power not only to have taken that place but Richmond.'
Historian Richard J. Sommers: "The purely tactical nature of the situation on 29th September brought forth Ewell's best military qualities. Such qualities had shown before, in those halcyon days ere the 2nd Corps had ever heard of Cemetery Hill, at first and Second Winchester, at Stephenson's Depot, at Cedar Mountain, at Strasburg and above all at Cross Keys. Yet great as were his accomplishments then, they do not equal his achievements this day. Acting in the face of imminent disaster to forge and sustain the continuous line from Fort Gilmer to the James that bade fair to contain the Federal breakthrough and save Richmond was the greatest contribution Ewell ever rendered to the Confederate cause."