With CO's dominant hub in place for years, many of the legacies have reduced service and frequencies to EWR. At this point, I think DL only serves ATL, CVG, and SLC from EWR (and we're lucky to get 757s on the ATL routes.)
But it wasn't always this way. DL has had a moderate presence at EWR throughout the 1980s and 1990s. They used to fly to FRA, LAX, DFW, MSY, PBI, FLL, and MCO at various points in the early 90s, with the florida routes sticking around until 2005 when they cut Song out.
So if you can recall, what have been your experiences on DL out of EWR? What gates, frequencies and routes have they tried and failed at (or maybe sucessful at for a while?) There's plenty of other EWR folk on this forum so I'm sure there will be some good posts.