I'd like to preface this by saying that I'm open minded and willing to discuss what's below as well as to being convinced of a different view:
DWONSC3 Tourney Balance true solo fail [example]. Most career and weapon combinations are forced to hold block and kite against high pressure. This reduces the number of actions a player is doing and capable of till pressure decreases. Boring. Some careers can deal with high pressure with single or few actions that deal massive damage (OE triple bomb fire+explosive bomb) or massive stagger (Tourney Balance Foot Knight charge). Reductive. Less complexity.
Witch Hunter Captain and Rapier is one of the few that keeps playing the game to its fullest extent under high pressure. Note how the combination continues engaging with all mechanics under high pressure. Enemies are not greatly staggered; they are still able to get attacks out to threaten the player, and they live long enough to be a threat.
Now, picture a team of four players playing like this, kiting together. Kiting against the horde. This has always been what I had in mind each time I discussed balance. Wouldn't it be great if most careers and weapons could do this?
Examples of Rapier's effectiveness in sneaking in attacks:
02:35 Chaos Warrior
03:24 Chaos Warrior
Warning for my subjective opinion (which I am very much open to discussing and being convinced of other views): To sum up:
"Billhook is so boring. It just holds block whenever there's high pressure."
I have enough experience with both weapons to say this. I was afraid of offending others before. I shouldn't have been. The above is true.
Safety? No. Safety connotates an inferiority to less safe weapons at sufficient levels of skill. Rapier has more capability than Billhook.
But I would be happy to be proven wrong about Billhook.