User blog comment:Gundam Legilis/Volume 1 Weapons In Depth- Myrtenaster/@comment-24260323-20140614062735

First and foremost, a rapier is a Civilian Defence Weapon, not a weapon used on the battlefield. An equivalent battlefield sword would be the estoc, a long and stiff weapon meant for thrusting against armoured opponents (preferably in their weakspots). Some estocs had no edge, but could still be used as a bludgeon.

Second, I think that Weiss' fighting style also affects Myrtenaster's effectiveness.

Weiss seems to use a "Modern" fencing style circum 19th-20th century considering the lack of an offhand-weapon or buckler.

IMO, if she had been using a "Renaissance" or Classical/Historical era style with proper equipment, she would become more versatile due to various options open for her in different situations. For example, daggers, lanterns, capes, wrestling and grappling are all parts of Renaissance Fencing.