Couple of observations from an interloper (USMA appointee parent). Hopefully, y'all wont mind me being here since I'll likely be offering advice (mostly learned here) to one DS's cousins when he applies to USNA year after next.
1) I'm noticing similarities in a lot of the DS/DD's still in the game. There are many still waiting that have offers to other service academies and/or ROTC. Since the service academies and ROTC programs profess to seek out the "whole person," it makes sense that those candidates that had the "right stuff" to get offers from another SA and/or ROTC are still in the game.
High WCS for USMA likely translates to high WCS for USNA and makes it harder for you to be cut early in the game.
If your DS/DD got the TWE this year and is going to give it another go for 2019, I'd try to make friends with a few BFE recipients and compare stats. The stars still have to align, but shoring up the leak(s) will certainly improve your odds.
2) Secondly, I'm curious as to how many still waiting have a Presidential nomination. From several posts on the USMA thread, it looks like USMA filled all their congressional slots before offering most if not all of the Presidentials. Does USNA offer Presidential appointments in a similarly late fashion? I know that they don't actually charge the appointments until after I-day, but I haven't noted many in the USNA appointment thread that identified their appointment as Presidential - if they would even know that since sometimes MOC's call on Presidential nominations if the candidate was also on the MOC slate.