Maxperson
Morkus from Orkus
1) If it's true that one type of fighter is objectively better than all others like that, it's bad design.The Slayer focuses 90% of its class features on slaying and thus uses greataxes and greatswords: the highest damage weapons.
Other warriors would go down to lower percentages by using one handers, polearms, daggers, thrown weapons, or bows.
2) It's hard to kill with your greatswords and greataxes when they're on the ground and such after being disarmed by the Battlemaster, etc.
Things are not as one sided as they may appear at first glance.