Looks like Will Shipley gets what he wants with Mountain Lion’s Gatekeeper. Within about a year, Mac OS X can be restricted to only run signed applications. With this setting on, chances for malware on the Mac will be even slimmer.
Nov-2011 – Will Shipley
My suggestion is for Apple to provide certificates directly to developers and allow the developers to sign their own code. And, by doing this, Apple can then reasonably say, “Ok, now we’re going to, by default, not allow the user to run any code whose certificate wasn’t issued by us and signed by a real third-party developer (except the stuff the user checks in the control panel).
February-2012 – Apple
You can choose to install and run apps from the Mac App Store and apps that have a Developer ID. Or you can install all apps from anywhere, just as you can today. You can even temporarily override your setting by Control-clicking, and install any app at any time. Gatekeeper leaves it all up to you.