Vista added a lot of usability features like window snapping and start search, but it's underlying OS was literally unfinished. 7 became what Vista, could've been and even Vista became usable when enough updates were applied.
7 disabled a lot of the security prompts for usability. It didn't remove them, it actually just automatically approved them. These days, most software doesn't need admin privileges anymore. You could always turn off all of the prompts if you wanted to, I think there were 4 levels of prompt severity?
