So my question is as follows, The requirements for Whirlwind Stance state
"Requirements You are wielding your staff, which must have the parry trait."
In the case of Staff Acrobat your "staff" is: Staff, bo staff, halfling sling staff, or any weapon in the spear or polearm group. So is the Bo Staff the only qualifying weapon for Whirlwind Stance, since you "staff" requires the parry trait? If so, doesn't this seem a little weird that an entire archetype about using your "staff" has a feat limited to a single weapon?