There's no need to make it any "harder" - the point is that just wasn't well-articulated to begin with. (Noting again that "well-articulated" is very different from fuzzy / ambiguous, in the engineering sense).

And given that the people you want to hire, by definition, are generally very busy (and have many, many important things to do with their time) -- even when they aren't currently working (despite the urban legend that "they always have jobs") -- as such, it just isn't a good use of their time.