Mandatory sandboxing increasingly seems like a misfeature. Now you can't install an extension that does a lot of things that are useful, ostensibly to protect you from malware.

Optional sandboxing can be good because users can have more confidence that something can't hurt them. But it can also be bad because users will have more confidence that something can't hurt them, and then it does anyway.

Meanwhile the ability to exercise arbitrary permissions given the user's authorization is something we've lost. And what have we gained, when the user just runs how_to_actually_uninstall_mcafee.avi.exe and gets the malware regardless?