Concerning Star Wars...well, here's the thing. Sci-fi and sci-fa usually have at least some connection to the real world, no matter how tenuous that connection might be. Star Wars in its 'primary essence' (i.e. the films) is far more of a fantasy story. It starts off with this in the opening crawl ("a long time ago in a galaxy far, far away" is a reference to fairy tales, just replace "galaxy" with "land"), has no connection with Earth or even our galaxy, and in its tropes (the Force, knights, swords, princesses, etc.) That's not to say that Star Wars can't rely on more sci-fi esque tropes, especially in the EU, but, well, I can't help but be reminded of how many fans disliked medichlorians, because it's introducing scientific analogy (mitochondria) to a previously mystic element. I wasn't put off by them in the same way, but I can understand the rationale.
To be honest, I'm on the opposite end of the spectrum from Kyrian, as I've always liked Star Wars the most when it's been using its fantasy rather than sci-fi elements. I remember one of the Republic Commando books I read by Karen Traviss (an author I've got very mixed feelings on), and while the book in of itself was well written, it didn't feel like Star Wars to me. Very heavy on military sci-fi and analogy to WWII paratroopers (by my reading at least), but these aren't the elements I enjoy Star Wars for (the fantasy/adventure/spiritual ones). For instance, I'm more charitable to the prequels than most, but my favorite Star Wars film is definately A New Hope, which is by far the most 'classical' Star Wars film, in both its story structure and style of film making. It's also part of why of the new films, I like The Force Awakens (more fantasy based) more than Rogue One (more sci-fi esque).