Absolutely. His loss just months before the battle of Gettysburg was devastating to the South. Especially when one studies how the first day of the battle played out.
There's no guarantee he would have made a difference. Lee was planning the reorganization of the Army of Northern Virginia from two corps to three for months prior to Chancellorsville and Ewell was always slated to get the new command. It is entirely possible that Ewell would still have been the commander coming in from the north on day one, and Jackson could easily have been the one coming in on day 2 instead of Longstreet.