If a where clause's binding expression ran after the body in an eager language, we couldn't use the value during the body. We'd be limited to using it from inside closures (manual laziness).
I do have ideas, but none that make sense. :-p It does seem better to embrace top-to-bottom side effect ordering throughout all syntaxes of the language, with as few discontinuity points as possible.
But if we want to embrace that, it's probably hypocritical if we use prefix syntax for procedure application. ^_-
