This article concerns warrior and rogue talents. You might be looking for the human racial Mace Specialization, which increases your Mace skill by 5 points.
Overview
The Mace is a very symbolic weapon, often chosen by Paladins and Shamans as a potent and extremely functional talisman of justice, representing a certain weight of authority.
To the professional soldier however, it is a different sort of weight, and how best to apply it, that matters, and if used properly, this adaptation of the simple carpenter's hammer can shatter bones and rupture internal organs, but the real mastery comes in the hidden finesse of knowing exactly where to hit and how hard, to cause mental impairment as well.
The inherent symbolism and humble origins of the Mace tend to appeal to Humans the most...
Diminishing Returns
Mace spec, like other abilities that are a passive chance on hit rather than activated abilities, does not affect diminishing returns in PvE or PvP for either rogues or warriors.
Rogue Functionality
Mace Specialization gives Rogues a passive chance on hit to stun an enemy for 3 seconds while wielding a mace. It also increases Weapon Skill with maces by 2 per rank taken.
Prerequisites: Combat 20
| Rank | Effect |
|---|---|
| Rank 1/5 | +1% Chance and 2 mace skill |
| Rank 2/5 | +2% Chance and 4 mace skill |
| Rank 3/5 | +3% Chance and 6 mace skill |
| Rank 4/5 | +4% Chance and 8 mace skill |
| Rank 5/5 | +6% Chance and 10 mace skill |
Warrior Functionality
Prerequisites: Arms 20
Mace Specialization gives warriors a passive chance on hit to generate additional rage stun an enemy for 3 seconds while wielding a mace.
The proc chance (and possibly the rage per proc) increases with each rank of the talent. In addition, the proc chance is higher with slower maces (and conversely lower with slower maces), though the additional rage per proc remains constant relative to weapon speed.
According to Ommara's post on 12/13/2006, the rage per proc should be 6 and the approximate proc rate for give weapon speeds are (both, presumably, at max rank):
| Weapon Speed | Approx. Proc Rate |
|---|---|
| 3.80 | 11% |
| 2.80 | 8% |
| 1.70 | 4% |
Editor's Note: More information is needed here about approximate proc rates and rage per proc for lower ranks of the talent.
Notes
For a period after 2.0.1 Mace Spec had an abnormally high proc rate. A hotfix for this was announced on the European Forums by Ommra 12/13/06 and on the US forums by Tserc later that day.
A somewhat less useful Specialization, the Stun chance even at 5/5 is still too low to reliably count on in a fight, kicking in once in every ten to twenty hits, dependant on several factors. Obviously dual wield rogues (or arguably, fury warriors) would benefit the most from this.
More reliable Stun effects for the Warrior include: 
[Charge] (1 sec, 100% Success), 
[Intercept] (3 sec, 100% Success) and 
[Concussion Blow] (5 sec, 100% Success). While rogues must restort to 
[Kidney Shot] (stuns per combo points used) as a finishing move. However, Mace Specialization does have the benefit of being a passive effect, requiring nothing more than the Warrior or Rogue use a mace for attacks.
This can be more useful to Humans due to their racial Mace Specialization, but since all Humans get a similar bonus in swords, it would probably be more useful to take 
[Sword Specialization] up instead.
Go to Warrior Talents Go to Rogue Talents