I am still to see good reasons (save for time) as to how Star Wars and Star Trek cannot be merged and a story be told that's true ST and true SW. SW things could be just things never mentioned/known on ST and viceversa, or maybe known under different names.
While it's true that the Force is a metaphysical thing for the Jedi, it could be just science for a ST-centered civilization. Subspace and hyperspace are not mutually contradicting. ST technology uses subspace technology while SW uses hyperspace technology. Both subspace and hyperspace can coexist.
The real problem for a true SW/ST crossover is that the galactic civil war against the evil empire took place "a long time ago". How long ago? I'd guess it was thousands of years ago, but it could have been hundreds of years ago. So while ST takes place in our future, SW takes place in our past, maybe with thousands of years in between.
A long time ago from when? If it was a long time ago from a point that's a long time in the future, the Star Wars Galaxy could be our own galaxy in the distant future. Basically its another way of saying "Once upon a time".