I do find it odd that the equivalent feat for melee fighters - power attack - is considered uber while this feat is considered weak. They both do the same thing: trade bonuses to hit for bonus damage.
PA (with a two handed weapon) trades +8 damage for a -4 to attack, +12 damage for -6 to attack and +16 damage for -8 to attack. Although it *can* be used in a full attack action, it is usually pretty inefficient to do so.
Manyshot gives you (almost) double damage for -4 to attack, triple for -6 and quadruple for -8. That usually averages out to far more than the bonus damage for PA for the same penalty. You need to do +4 damage at 6th through 10th BAB with your arrows, +2 damage at 11th through 15th BAB and +1 damage at BAB 16+ to exceed the effectiveness of PA. Your 'typical' 16th level ranger's bonuses to damage with a bow (+4 for favored enemy (no longer precision based), +7.5 for a +4 flaming bow, +6 for strength, +1 for prayer on top of the 4.5 average damage) results in an extra +69 to damage for a -8 to attack. Even if we don't give him a +4 flaming composite (+6 strength bonus) bow or favored enemy bonuses, that number is still going to be far higher than the benefit of power attack.
Yes, there are differences: PA helps overcome DR (which should be less of a problem for an archer with a variety of arrows) or hardness. PA sometimes is useful in a full attack while MS is never useful in a full round action. PA can be combined with some special attacks while MS must be used as a lone single action. PA is multiplied in a critical hit while MS only multipies one arrow. It is easier to full attack with a ranged weapon than a melee weapon. Yada, yada, yada ... There are differences that favor PA, but MS does give you more damage in exchange for a smaller to hit penalty than power attack.
My point is not that these feats are identical - it is that these feats share a basic core component (trade accuracy for damage) and one is considered (by many) to be uber while the other is considered (by many) to be too weak. That just seems odd.
