In reply to Ed.

Theme Check is already mandatory. If a theme fails on any required or warning stuff from that, it doesn't even get uploaded to the system.

The more automation the better. Contributing to that plugin would be a great way to help both the team and theme authors out.

There's only so much such a code can do though. For example, it can't tell us that a theme is licensed correctly. It can't distinguish between genuine and spammy links that are hardcoded. It doesn't know if custom post metadata is related to the visual design vs. holding content. That's why we still have human reviews (though we'd like to get away from having to do initial reviews before making themes live).