On the website settings page, it would be nice if there was a toggle to lock a website so that changes can't be made accidentally. (And when you go into designer it could show the "your changes won't be saved" message, like you get when viewing backups.) 

I'm terrified that I'll be poking around a website one day and accidentally make a change, not notice it, it gets autosaved, and it then gets pushed out in a publish at a later date. 

It makes me paranoid about going into designer ("what if I bump something?") and publishing ("what if I bumped something ages ago and now I'm publishing it?")

I know there are backups, but that wouldn't stop me making that mistake. It would only allow me to roll it back if (and when) I notice it.