In a literal sense, Sci-Fi novels or the like in the SW-verse likely revolves around expansion of what's possible through the force into the unknown (is my guess). Similarly, in 'our world', we take what we know of through science and expand upon it, making connections to what would otherwise be impossible had it not been for a singular 'unknown' assumed true. An example would be pyrokinesis. Assuming the force is existent, one could influence molecules into a rapid vibration, eventually achieving combustion. Considering such an unknown but accepted concept exists in our world as well (e.g 'mass'. Why does mass exist, from where did mass come from and originate), in which we simply take it as a given law of the universe and make sense of what we can, in the SW-verse likewise is what would probably occur. To that extent, I'd say SW Sci-Fi is probably Fantasy. For example, some sort of 'magic' that allows the literal breaking and surpassing of universal laws. I am not well-acquainted with the Star Wars universe, but as far as I am aware, one cannot simply create energy and mass from nothing. One cannot conjure conjure blasts of tangible, physical balls of energy from their palm that break down and disintegrate whatever they touch. One cannot tame a sentient, organic flying rug from the depths of a dungeon beneath the sand which houses a magical genie that can grant nigh any wish with whimsical ease.
Just as likely, there might be some sort of sci-fi more centred around a singular group or race, in which some of their limitations prevent them from accomplishing something, whereas those of another race or species can. For example, the breeding of a Yuuzhan Vong and human who fulfills some sort of prophecy determined by the mythological god Minerva, destined to take grasp of all the planets of the galaxy to destroy the world-egg and escape the supposed confinements of physical form.
Really just anything impossible, but loosely explainable through science if one adds a non-existent element to their fictional world (such as 'the Force', except not the force since they have that, I guess :| ).