The Start Screen was basically a large, random selection of programs and shortcuts (many of which I had never seen before!) flattened as tiles with no discernable organisation.
The All Apps view is simply every clickable element of the start menu flattened as small tiles.
The "Modern" apps are still vastly inferior to their desktop counterparts and I still see absolutely no use for them on a traditional, non-touch PC;Also, I like to have my taskbar on the left, but on the Start Screen the "back" functionality is hard-coded to be the lower-left corner of the screen. It's only intuitive for those keeping the taskbar in its default location.
Also, "SecureBoot isn't configured correctly"?...I'm hoping this is a temporary issue.
1) Organize it, it's only as organized as you are.
2) Agreed, though I've never had a need to use the All Apps view myself. It does just look like a mess.
3) Try Mail app snapped 1/3 or 1/4 screen. Fantastic app. The new Facebook snapped. The alarms app is great though I have feature requests. One of the absolute best Modern apps is Newegg. I shop there a lot for business and personal and it's one of the best. All the way through even the shopping cart and wish list, all Modern UI. Only negative is it doesn't scale so well smaller than 1/3 screen snap.
4) This may be a case of majority rules.
5) This just means you have UEFI SecureBoot and it's not configured? Have an HP by any chance? If so, download the HP BIOS GUI app and enable it. I had to do this on my ElitePad. Otherwise, just go in you BIOS and enable secure boot.