It has been in talks for quite awhile now that the Soundstages directly adjacent to the Lower Lot would eventually turn into theme park space. Something Potter themed for this space, however, simply doesn't make sense. Excuse the following rant, but I have a lot to say on this matter:
A Ministry of Magic expansion has been rumored to hit USF for a long time coming (particularly replacing Fear Factor Live so that it is situated next to Diagon Alley), but it just doesn't make sense. Those familiar with the books and films know that this particular location is a governmental wizarding establishment, so how would you translate that into a theme park experience? There are no known dining venues, shopping locations, or anything that could logically be turned into a ride or attraction. The only experience that could possibly be offered from a location like this would be a walkthrough, but that would be an immense waste of theme park space. An expansion like this would put the minds of Universal Creative to extensive strain, even more so than what they did to enliven Diagon Alley (Horizont Alley, Carkitt Market, etc.). A location like the Ministry would bring across so many logistical hurdles. For example, how would we enter the building? Through a large show building entrance like Transformers or RotM? Not possible. I could go on for days, and I apologize if my Potterhead rant comes across as rude, but my point is that this just doesn't work out.
My suggestion for this space would be to keep on eye on other Universal properties.