If it could be toggled between on, off and feign either, that would be insanely OP. People would never know if a bard was actually near death. As it is, after maybe two fights you know if a bard has either edge (most assume bards have weakness) and it ceases to matter for the most part.

The problem with the feign edges to me is always this.

Feign strength- You look healthier, and maybe opponents flee instead of finishing you. Except opponents in control of the fight don't care if you die in four rounds or six. Bards are not scary in passive melee and have crap for ability to lag opponents out. Fights you are in control of, opponents are leaving earlier because they don't think they are in as much control or that they have a shot to swing it to their favor. This means you're pretty much screwing your ability to kill them because you can't keep them engaged as readily in the fight by stringing them along. Great for maybe survival, horrible for landing PKs. Nobody has ever cared about being the most survivable bard. (well, besides my overly conservative self)

Feign Weakness- Most vets assume bards have this, know general hp levels of classes, can assess gear bonuses, and track their own damage output. After maybe two fights, you know if a bard has the edge. They might over commit to a fight, but in most cases where they see a bard convulsing, the bard dies anyway. In close fights, they are probably going in knowing it is close anyway. People decide to flee when looking at their own chances and their opponents, and most weigh in this edge into making that decision when comparing their health to the bards.

The only way a bard can really maximize feign weakness, is to feign it through his actions as well as having the edge. This means fleeing at 50% health, maybe 60%, because you know you look writhing to them. It means not blasting away at people that are gushing when you know you look to be convulsing to them. The only way the edge is useful, is if people genuinely don't know, or have reason to suspect that you have it. And that's a lot harder to pull off.