To me the idea of ‘crowd sourcing’ such an app, like Wikicamps does would be the only practical method of keeping the info relatively up to date for users. This notion of ‘analysing user route data in the cloud’ sounds somewhat ‘pie in the sky’ if you’ll excuse the pun.
What user data in the cloud is likely to be available & updated regularly for any but the major tracks? Info which is already readily accessible from state road authorities? That may be worthwhile putting altogether into a single app, but I suspect is less than many folk here would want.
If talking about 4wd tracks (eg. High country tracks or Simpson crossing tracks) as opposed to the main connecting outback tracks (Eg. Birdsville or Oodnadatta tracks) to rate I just cannot see that sort of info being available on an up to date basis (in which case it is pretty useless info) without regular user input. I guess I could be wrong & perhaps you know of regular & reliable info sources I am unaware of, but I’d be surprised.