WUSTL is now not considering demonstrated interest but ED is demonstrating interest.
First off, I would say - which school are you interested in more - that’s where you should apply? Everyone has a favorite - so to say which should I apply to - means which can I more likely get in.
That’s great, but what if you prefer one over the other?
That said, I’d apply to WUSTL but yes, test optional.
I suppose it depends on where you want to be and what you want to study, and WUSTL is a tougher nut overall although BU is not easy - but with your stats (minus test score), I’d go big!!! - assuming again, that’s where you actually want to be.
I mean, they are so different - small vs. medium/large…enclosed campus vs. city. Urban vs. suburban, etc.
You should go for the one you want…
PS - according to the common data set, legacy is considered at wustl - does that go to the grand parent level? you’d have to ask a counselor - but i would not apply/not apply based on legacy.