I concur. Trying to crank out a really awesome critical wielder takes a lot of specialized abilities:
+3 falchion, 18000 gp
scabbard of keenness 15000 gp
pearl of power (3rd level) 9000 gp
Assassin's Senses (Clr2, Sor/Wiz2, Brd 3, R&R, non-Wotc, non-core)
Improved Critical feat, +8 BAB
Weapon Master (feats: Dodge, Mobility, Combat Reflexes,
Expertise, Weapon Focus, Spring Attack, Whirlwind Attack, Dex
13+, BAB 5+.)
Assuming the character wants to be self-sufficient he needs to either max out UMD and take a level or two of Rogue or Bard, or sucks it up and takes three levels of Cleric so he can cast Assassin's Senses 3 times per day with his pearl of power. He takes the War (for weapon focus, hopefully there's someone with a falchion out there) and one other appropriate domain. Searching around in the FR book, there's Anhur, a deity with Chaos, Good, Strength, Storm and War whose weapon is the falchion. War and Strength domains it is.
Stats he assigns DEX 14, STR 14, WIS 14 (for the bonus spell and for Superior Combat Reflexes). The rest are also important, but CHA is a dump stat, abnormal for a cleric.
(Human Feat) Dodge
(level 1) Cleric - War domain -Weapon Focus: Falchion
(level 1) Combat Reflexes
(level 3) Cleric - Mobility (3rd level Feat).
Then the character jumps into Fighter until he can squeak into weapon master.
(level 4) Fighter 1 - Expertise
(level 5, BAB 4) Fighter 2 - Spring Attack
(level 6, BAB 5) Fighter 3 - Whirlwind Attack
(level 7, BAB 6) Weapon Master 1
(level 8, BAB 7) Fighter 4- Weapon Specialization
(level 9 BAB 8) WM 2- Improved Critical
(level 10,11,12, BAB 9,10,11) WM 3-5 - ???
(level 13,14) WM 6,7 - Ki Critical.
Now the character is ready to really rock with his critical bad-self. At 14th level he's spent ALL his feats to achieve this save one at 12th level. He gets a BAB of 13, +2 for Superior Weapon Specialization, +2 for STR and +3 for the weapon, so his final modified attack bonus is +20.
His Falchion crits on a 10-20. Base 18-20; Keen 15-20; Improved Critical 12-20; Ki Critical 10-20.
When he casts Assassin's Senses (for 3 rounds at a time, with a pearl of power he can do this 3 times per day), his critical increases to 8-20. weeeeeeeee.
His base damage bonus is +3 for STR (two-handed), +3 enhancement and +2 for superior weapon specialization. 2d4+8. Once per day he can increase his STR by 3 using his clerical Strength domain, but this yields only a +1 to hit and +1 to damage.
Since he's a weapon master, with his chosen weapon type 7 times per day he can do maximum damage when he doesn't crit. On those occasions where he does crit, 3 times per day he can increase the crit multiplier to x3.
Normally he does 2d4+8, or 16 points of damage per hit. On the first three criticals, he'll do an average of 13x3 = 39 points per hit. A 14th level character is assumed to have 150,000 gp of wealth and he's only spent 42,000 gp. There's not much else to boost his critical range, so the rest can be plowed into increasing the base damage of his weapon, other items that increase damage (rhino hide armor) or strength (belt of giant's strength) and defense (since he can't wield a shield unless he takes Monkey Grip as his level 12 feat, but I'd recommend using Scribe Scroll so he can cast Assassin's Senses more often).
Personally I don't see any of this as broken. Any uncrittable monster (elementals, undead, constructs, characters with armor that ignores crits) will just ignore this character, so the weapon master will be saving his maximum damage ability for those targets.
The rest of the time he's going to crit about one quarter of his swings. To achieve this, he's spent a large chunk of money and a bucket of feats. I don't see the imbalance here. Maybe someone can post a more specific example? I could've tweaked this one out at a lower level, but wanted to include Assassin's Senses, since it's part of the "broken" combo I've seen mentioned.
Greg
We'll ignore graft weapon, since it doesn't increase criticals and we'll ignore duo-dimensional hand, since it specifically disallows critical ranges to increase beyond 17-20, and we'll ignore the deepwood sniper route, because their keen arrows ability because it specifically doesn't stack with any other keen effect. I'm also ignoring Hunter's Mercy because it's only with arrows. Also, the weapon master's flavor text strongly implies it's with melee weapons only.