Pretty ironic that you're actually listing more things why I would not use AWS at all. You mention: "stay away from", "ensure that you", "reasonable caching", "bandwidth is the only real nightmare" are all huge red flags.
Instead of interesting technical challenges I now get to worry about the minutia of Amazon's billing system. Neat! Where do I sign?
There are parts of AWS that feel like magic and parts that cause me to bang my head against the wall, overall I like it more than it annoys me so I use AWS but it’s not a silver bullet and not all workloads make sense on AWS.