I personally think the entire medical process is a bit random and has a lot of luck involved but of course you have to have put in the work before to put yourself in a position where you can take advantage of the luck, but ultimately in my opinion getting into a UC school requires work + luck, without either one, it's almost impossible to get in.
I'm a Cali resident and applied to all five. Got interviews at UCSD, UCD, UCLA, no news from UCI (decision pending), and rejected at UCSF w/o an interview. I agree with the above poster that UCD seemed to focus very heavily on service. I'm not entirely convinced that UCSD is very heavily number focused. I did not think I had a very good shot while sending in my secondary and after interviewing and talkin to fellow interviewers that had much higher MCAT scores than me and interviewed at a number of top schools, I thought to myself on the drive home that that was likely as far as I could go with UCSD. A few weeks later, I got accepted at SD but rejected at Davis, and I'm still waiting to hear back at LA. With so many very well qualified applicants, UC schools have the luxury to be very very picky, and I remember a number of Deans during my interviews telling us that you're here because we know that you are academically qualified and that you can withstand the rigors of a medical school curriculum. We know you can graduate medical school. The question now is your personality and how you interact with people. Before, I thought they said those things just to calm us down but now, I think some schools do really stick by that statement especially the UCs. So, I think for candidates, you should maintain high enough stats to convince them that yes you can get through medical school but beyond that it's about being able to make yourself stand out during interviews and on your application. Do something unique and have a lot of passion for it (it shows) and it doesn't have to be related to medical school. At almost all my interviews, my interviewers focused very heavily on an activity of mine that had nothing to do with medical school, and they were all decently intrigued by it.
I guess to sum up everything above - your numbers convince them that you're intelligent enough to graduate medical school, your interviews + your activity convince them that you are an interesting person that can contribute to the diversity of the class. But even having said all this, I still do think that you need a fair amount of luck to get in - it depends on who reads your app, who interviews you, and whether or not you can find a common basis with your interviewers in a very short span of time.
