To some of your questions:
- I have bony clavicles, so I'd always go with wider shoulder straps
- No problem with gear coming out at the bottom of the zipper
- Water resistant is probably the best word. If you're in a downpour it's going to seep in, but a mist or light shower should be easily repelled by the fabric.
- Fabric feels thin (it is, and is light) but it is remarkably strong and durable. I've scraped boots and poles and snowshoe crampons against it and it doesn't look any worse for wear.
- No interior compression straps, other than the one at the top, but it's more of a front-to-back strap cover.
- Interior is one big bag, with a sleeve against the back sheet that you can stuff things in. The removable top pack is pretty big though.
- I get some squeaking somewhere in the back sheet pivot when I hike, it's a little annoying. Haven't figured out how to get rid of it.
- Overall, it's great if you want something light, well-built, and without a ton of bells and whistles. I'm happy with mine.