The reason you didn't see the bevy of popups was because you did a clean install. With an upgrade install all of your existing apps have to go through the same security steps as a new app, and they tend to do it all at once, especially if you have a lot of apps that launch at startup. That said my experience was not as extreme as some of the screenshots, and I think it would be even less for the average user. And of course this is only upon first upgrade, so while frustrating, you quickly get over it.