What's going on with the wars is critical as far as how it directly or indirectly it ties into the Empire's rise. At the moment I've been internally considering making Mandalorian invading force something so genuinely frightening and creepy that it would make as to why so many embraced someone like Palpatine and initially welcomed the initial militarization of the Republic.
The enemy threat bringing about the war to me has to be largely external to differentiate it from the original trilogy, but also a touch internal to demonstrate how rotten much of the inside of the Republic has become over time. Hence the external threat of the Mandalorian invaders, and the internal threat of criminal Traezin Crayde selling out the galaxy in exchange for absolute power. Crayde, a man who might not have become so big a few centuries before when Repulic laws were better enforced, now powerful enough to be a partner with an invading horde.
Aesthetically I've been thinking about moving this Mandalorian Coalition into an image of cold, unnatural biology vs. the warm, plain humanity (for lack of a better term) of the Republic/Rebels vs. the Empire's cold technology. The clones themselves, falling into the uncanny valley, looking just too symmetric and always seeming off in contrast to all the various little flaws and quirks of real people. The Mandalorians, (as I've been considering) walking Frankenstein monsters of a sort, literally stitched together with their own parts and those of other races in the name of having better biology. Beings visually representing what they plan to do to the Republic once its conquered, taken apart and then put back together for its own good.