Anytime I have been in a department with a job search going on, I have gotten emails from perspective applicants asking what the committee is looking for. Applicants assume that there is some secret agenda that the committee didn't want to come out and say in the job ad. I can only presume that people believe committee members desperately want to sort through dozens of irrelevant application packets, as well as waste the time of hundreds of others (applicants + letter writers).
In fact, academic job ads are often as specific or as vague as the search committee wants them to be. There's certainly too vague, IMO. But if the committee is multi-disciplinary it would not be surprising for an ad to be somewhat vague to cast a wide net. What potential applicants should be aware of is that the "committee" doesn't want anything. Each person on that committee has an idea of what they are looking for, but those desires might be conflicting or directly opposed to those of other committee members. Again, IME, the more focused ads reflect a stronger agreement by the committee (and possibly department) with regard to what they are looking for.
All you can do is read the ad and put your best foot forward. A lot will come down to whether there is someone on the committee willing to go to bat for you to make the short list. If the job is departmentally centered then the within department members will have a lot more say as to who gets an invite than the outside members. If you are in a position to gather information, it might be useful to find out what the department feels it is missing, but maybe not. There is no secret plan or desire to draw in the most applications, only the hope that the search yields a solid pool of interviewees that the committee can evaluate and fight about.