Haven't heard anything about HD from WILM, but my guess is they will eventually do that, especially as more people get HD radios. So far, I don't know of anyone who has an HD radio so whether it's WDEL on WSTW HD3 or WRTI's HD services (they air jazz during the day and classical at night on their HD2 station, which is the opposite of their on air schedule) or KYW on HD, etc it doesn't make much difference or will catch much attention unless you have an HD radio.
It's ashame that Allan Loudell isn't still at WILM where he basically programmed the station as he pleased, prior to the CC takeover. I could image all sorts of documentary programming airing on a WILM HD2 that they'd not be able to air on the AM station. Both foreign and domestic programming. I don't believe Loudell gets to have much say in programming at WDEL other than what interviews he does on his newscasts. But maybe Delmarva will ask Allan about that sort of programming for a WDEL HD2.
WDEL has been working hard to make a market for themselves, in the upcoming post AM radio world, with their internet site, online listening, Pod Casts, Various WDEL Blog sites, and their video newscasts, etc, as AM radio continues to decline, so it does make sense that they'd be involved with HD radio programming too.