That is roughly how I've approached things whenever I'm walking into a pre-existing situation. I spend the first week just reviewing everything and writing down questions/observations, etc. Not only the "WTF" moments, though. I also take note of things that I think work really well or were really great ideas.
Then there's some time to review/prioritize/etc before any sort of discussions.
Then there's some time to review/prioritize/etc before any sort of discussions.