That is the largest capacity aircraft in DL's fleet that does not have a mid-cabin lavatory. Definitely sucks for C+. I imagine they wanted to prevent a crowd standing around up front, but...

If I was in C+ I would send a polite note of inquiry to DL about that policy and how it might change when a rear lavatory is down. I mean you can easily see from most C+ seats if the front lav is open so if you just get up when it is unoccupied, it should not be a disruption at all.

It is obvious from the new boarding structure that DL is really trying to create value in C+ and this anecdote is a great way to point out a negative value to C+ if this truly is policy.