Currently, the weapon is tuned a bit oddly.
The ability to hold parry for 40 seconds is clearly overtuned, but the weapon as a whole is probably undertuned.
This weapon's closest competitors are the Heavy Mace, the 2hh(worse hm), and the War Club, so I'll be primarily using them for comparison.
Thematically, the quarterstaff is intended to be a powerful defensive tool and to allow players to survive in quite rough situations even if it doesn't have the ability to go slash crowds like a war club(fast, long).
To that extent, I consider its damage values fine.
Slash may be a bit too anemic on range, so extending just a bit would probably be good if only to allow qs players to catch more counters.
Stab range seems fine, maybe just a slight boost there.
Overhead is the bread and butter of the weapon and is still a great tool which offers qs its "dual-range" interactions.
Defensively, the qs is worse than heavy mace right now due to getting range diffed too hard(forces using heavy swings to chase or leaning too predictably into overheads, costing stamina) and only having equal stamina damage negation.
40 seconds takes too long to drain for "not getting hit at all" as well, punishing the use of drags too heavily against quarterstaff.
One thing to avoid is allowing infinite stamina on riposte as well again.
To that end, the most you should be able to hold parry for is probably 20-25 seconds, offering the qs what is still a uniquely powerful defensive tool, being able to "hold parry" and have it affect you half as much as other weapons.
Having drags be usable to punish holding parry on qs would also allow its stamina negation to go higher as well, up to a maximum of probably around 30% with its current tuning(if you buff slash and stab range probably max at 25% or so) before it becomes possibly too strong.
These are levers which could be pulled to make qs an interesting and still thematically powerful option in-game. Currently it's simply overshadowed by other options.
