I'm interested in hearing your thoughts on this. Reason I ask is ....
My thinking has been along these sorts of lines:
* the game defines a club as d4 and light, this to me suggests a small wooden stick held one-handed and because it's light, can be dual-wielded escrima style
* the game defines a quarterstaff as versatile d8, this to me suggests a thick stave as tall or taller than a man, made from very strong wood, shod with iron and used two-handed
* the game defines the BA atk granted by PAM is a d4, this to me suggests that the butt of the polearm is acting like a club, and typically the haft & butt of a polearm is unlikely to be either as stout as a quarterstaff, or iron-shod like one, so this makes a great deal of sense to me
All of this suggests the following things to me
* a shorter, slimmer staff that is not iron shod, such as a Japanese "jo" staff, could logically fit in between and could be used either one or two handed, as is indeed the case in that fighting style
* a baseball bat is smaller than either type of staff, but larger and more weighted than an escrima stick, and while it could be used one-handed, is typically used two-handed
* both of these make much more sense to be able to be used one-handed than a quarterstaff
So, I've been thinking of having 3 weapons as follows:
* club, as written in the PHB, d4, light
* short staff, d4 versatile d6 (no light property)
* quarterstaff, d8 two-handed (no versatile)
That way, you can wield clubs one-handed or you can dual-wield them (escrima style), you can wield a jo or a baseball bat one-handed or two-handed and they'll do more dmg if you wield them two-handed, and you can wield a quarterstaff for the greatest damage, but not one-handed.
This is functionally very similar to what you're proposing, the only real difference is your half-staff does d6 when wielded one handed, whereas mine only deals d6 when wielded two-handed, however mine has the option of being wielded one or two handed.
Do you think d4 versatile d6 is too weak for a jo staff / baseball bat type weapon ? Is that why you went for d6 one handed ? Or did you have something else in mind ?
Of course, happy to hear anyone elses thoughts too, not restricting this to just one person