Yes, let's make all do the same damage, why then use medium or red, when blue is the fastest? Yes, random twirling fights are the funnest! or not!
No offence, but you sound like a newbie.
If you only use one stance then you can either be classed as a:
1) Newbie who don't know how to change/use different stances.
2) Roleplayer who only plays with one kind of stance.
Believe it or not, but sabering is not about CHOSING ONE STANCE, is about using them all, at the correct time.