If DL is indeed removing J seats from the UD and replacing those with E+ seats, then perhaps they could extend the J cabin on the MD past the 2L/2R doors. Kinda like what NW did with the 747-200s. J went past 2L/2R and Y started just before the wing area.
http://web.archive.org/web/200206020...0z/index.shtml
Something like this