and the guy with the staff isn't able to fire off "well-aimed high-speed" power hits
I never said power hits, but in comparison to a sledge hammer, it will be well-aimed and high-speed. If someone tries to swing a sledge hammer at me, i could take a nap, read a book and then take a step to the side, and the guy will miss.
With light, blunt-force weapons like a staff, which have relatively little mass to add to their momentum, almost all of their impact force is generated through velocity. That means "high-speed" hit
is a power hit, as inevitably as F = M/2 * V^2.
Unless, of course, you meant to say "rapid" not "high-speed," in which case it's quite possible to get several times as many hits in as someone using a sledgehammer. However, unless you catch someone in the nuts, throat, or other similar squishy bit, such quick, uncommitted jabs are only going to be annoying and distracting rather than actually debilitating. For a Staff to cause physical trauma bad enough to warrant a "P" damage code, though, those kinds of love-taps just aren't going to cut it.
By the time you finish winding up for a shot that
will do some damage, the guy with the sledgehammer is going to crowd in on you and crack your ribs with a thrust from a 10-pound chunk of iron on the end of a handle that lets him get a sturdy 2-handed grip and put his hips into it. That's because the sledgehammer has many times more more M, so needs far less V to make the same amount of F when it hits.
a Sledgehammer is going to be used for blocking and quick thrusts/jabs
If you use it like that it will probably to as much damage as rifles butt (str/2+1), be useless against concrete walls and is not comparable with a mace. Your comparisons really don't fit together.
You've apparently never used a mace, tried to butt-whip someone with a rifle, nor used a sledgehammer for any form of utility task, either.
With its mass you only have to apply very sparing effort to do things like batter down doors, break 2x4s, smash through sheet-rock, and other such trivial tasks... most of which a rifle-butt couldn't do on its best day. Taking a full, two-handed 'baseball' swing to break a human ribcage is just plain overkill. However, there's no reason to apply anti-personnel techniques against a stronger, immobile barrier where you can take the time to wind up. The hammer can be used in either capacity
as required by the situation, so don't try to throw up a straw-man by acting like it has to always be used one way or the other.
Besides, didn't
someone just say that the DV of a melee weapon was supposed to be
several actions taken as a whole? Based on
that principle, the aggregate damage caused by 2-3 of hose lighter strikes in quick succession against a moving opponent is going to result in trauma equivalent to one massive strike, but be far easier to land.
Seems they actually have one-handed Maces written up in Arsenal p17 as Str/2+3 Reach 1. Since the Sledgehammer is basically a bigger, 2-handed version of the same thing, bumping the DV up by 1 or 2 giving it a point of AP and an extra point of Reach
Afterwards you could reduce the DV by 1 or 2 for the reduced hitrate, and calling it a day sounds about right.. SR has it already well thought through.
Which pretty much balances out to Str/2+4, AP -1, Reach 2... which is roughly what was being suggested in the first place.
Now, I'm going to go to bed before I say something that will make Fastjack upset.