>It's carefully balanced so that going red or white will be about equally valid strategies. Making it so that aggression is the best choice removes the strategy from combat.
It's not about aggression being better. As it currently stands, though, it's inferior to playing defensively. The core rules and supplements even point this out explicitly, suggesting that players fight with a mind more towards defense.
>Thus removing the fun of earning new techniques as your character gets better, and the cool changes of strategy that result from the introduction of new maneuvers. Oh, and also making it so that beginner players have to learn a huge number of maneuvers at once.
Except that some (like Master Strike) have ridiculously large requirements. Draw Cut, Wind and Bind and Mordschlag are already low-Proficiency moves anyway.
>It's already really, really good for what it is (a way for very good fighters to instantly kill weaker fighters), and you want to make it better?
Except this isn't the historical reality of the technique. In meatspace, the Master Strike is supposed to be one's default method of fighting against all opponents once mastered, not something that gets tossed aside when you run into someone just as good (or better) than you. In fact, someone with better control, more general skill and better fitness could still lose to someone who knows Master Strike, because the whole concept is based around efficiency and minimising movement while attacking and defending in one motion.
Basically, there should be an incentive for using Master Strikes against all adversaries, not just inferior ones.