Definitely would be a significant site to preserve. Reynolds' spent his last night there, as related by The Emerging Civil War: https://emergingcivilwar.com/2015/06/30/gettysburg-off-the-beaten-path-moritz-tavern/ .
But the cost for cleanup would probably be prohibitive, and its location is well outside the park boundaries. I believe the ABT took on a similar chore (cleaning up a former auto salvage business) adjacent to Reed Bridge at Chickamauga, but the area around Moritz Tavern seems to be much more extensive?
Thanks for posting,
Dave