I'm not really sure if WSU focuses on rural medicine anymore than UTAS, as Tasmania is in its entirety rural. But yes, given its size RHH would likely see more complex cases than the WSU hospitals. The UTAS cohort also seems to be very tight-knit.
I would consider there's much more going on in Sydney; more conferences, more doctors, more connections etc. There is collaboration with UNSW and USyd so research would likely be stronger at WSU. The social life would also be better there, as well as being much more connected to the rest of Australia and the world (about to have a second international airport).
I'd weigh up the importance of clinical placements in a larger hospital (smaller hospitals can actually be better since you have more hands-on experience and closer supervision) vs the benefits that come with a larger city.