but... it seemed really obvious that Rey was going to be the main character. the fact that they had promo shots of Finn holding a light saber was certainly misleading... but there was never any real doubt that Rey would be the star of the new films.
besides, in contrast, Elba as James Bond was far more likely to be a reality than Finn being the main character in a new SW film. even then, Elba consistently dismissed those rumors.
your theory about how she'll just get built up as a big deal and then get side-lined certainly fits with tradition. I remember being disappointed that Michelle Yeoh got this sort of treatment when she appeared in a Bond film. yeah, I realize that it's a Bond movie - but I really like Yeoh, and was hoping that she'd get a bit more, I dunno, respect! it's still better than how they treated Chow Yun Fat in the Pirates of the Carribbean franchise, though.
honestly, my hopes for the franchise are smaller... what I'd like more is to have Massive Attack or Portishead do a new Bond song. after that dreadful Sam Smith number... well, I'd like an upgrade in the songs! and I always felt like either one of these groups could do a pretty fantastic Bond opener.