[tptacek]

Don't think about security that way; that kind of logic is misleading. Security is measured in dollars, in the sense of cost imposed on attackers.

You're right that there's a constant tension between features and security.

[comrade_ogilvy]

Right. To be more precise, security is a set of costs on web developers, web viewers, and attackers. There is no obviously correct way to balance all three, once you start seeing feasible removed/missing features that would be genuinely useful tallied as costs.