Most of my first lines were fairly generic as well. I think that's normal, seeing how you aren't given much flexibility in your introduction anyway. One thing I did try to avoid was starting with 'In X's novel, 'Y'....'. I tended to open with a framing sentence that briefly describes to where the book is set and its central ideas. This creates more of a 'funnel' effect where you move from general to specific. I found this read better than introductions where the reader is immediately dropped into a very specific discussion without warning.
Of course, the key word is 'brief' and I would never take more than one sentence to do all of this. Otherwise, your risk sounding too 'general' and 'not addressing the prompt'.