Great point, agree.Without my being a senior footy coach...
I'd go a step further and say that successful coaches think "defence first, attack second"
So when you change the rules, these coaches think about how to defend the new rule, and only once that is worked out and bedded in, then consider how to better attack without compromising the defensive aspects.
Vice versa, leave the rules alone and you'll start to see more attacking football. Change the rules and in the affected aspect of the game you start again on defence.
Just my 2c worth.