Some changes that would improve Avast SafeZone would be to update the browser to Chromium 17. The version it is using now is still 9 and there have been many security updates since that time.
Also, all plugins should be disabled by default, as they are a major security vulnerably. At the "about:plugins" page, there are many plugins enabled and their security could not be trusted. Flash should be disabled by default and the user should be given a choice if he/she needs to use Flash for a specific banking site. The Flash version included within SafeZone is also outdated, causing further security issues. The Flash version included is "10.2.154.12" and the current version is "11.1.102.62".
Google Gears and Google Update are included as part of the SafeZone browser and it would be safer to include less unnecessary software. Especially as they are developed by Google, an advertising company. Settings should be made more secure by default. For example, "Block third party cookies", "Never offer to remember passwords", and "Don't allow tracking of my location" should be enabled automatically.
I question how secure SafeZone is because what happens if a malicious plugin is already installed on a user computer. It is enabled by default in SafeZone and can cause as much damage. Also, SafeZone is not really isolated from the rest of your computer because you are are able to import data from other web browsers.
These changes would allow users to be more secure while using SafeZone.