Backtesting doesn't really work for this where user behavior, both by design and in practice, responds to the incentives offered by the rule set. Looking at past behavior under a different proposed rule set just produces misleading results.

The only way to get meaningful results is to put it into practice and see how users (not even merely existing users but also new ones) respond to it. Which is a key reason why it is so important to make only a few changes at a time, as steemitblog states in the post (and I support 100%)