The new BMW X3 has a much roomier rear seat than your X3. But it won't be more reliable than a BMW out of warranty.
Neither the Murano nor the Highlander is fun to drive. The Acura sort of is. It's probably the best fit.
I haven't driven the new Ford Edge Sport yet. It might deliver what you're looking for. I did recently post a review comparing the new Murano with the non-Sport Edge.
Maybe also check out the Dodge Durango, though it's probably larger than you need and doesn't offer a panoramic sunroof. A lot of room and drives surprisingly well.