I feel like it's a win-win, at least for me. I love the idea of the movie being a hunt for Luke, but if it's not I'll enjoy the surprise. Regardless, I'm usually able to turn off my expectations once I'm sitting in the theater. When the lights go down, I tend to "forget" almost everything I know.
That said, some kind of search-for-Luke plot is almost guaranteed at this point. Too many independent sources have reported it. The severed-hand-and-light-saber-floating-through-space thing could easily be misdirection, as could many other plot points we think we know, but I'd be willing to bet the house on the plot revolving around a search for Luke, to some degree.