While working on a way to be (as much as possible) a Paladin that kills far less often than she incapacitates (in the hope of redeeming her enemy), I noticed just how hard it is to deal non-lethal damage. Higher-level characters can rely on the merciful trait for weapons (and I intend to), but until you can afford that (or use your weapon bond liberally), there's almost no recourse for lower-level characters to not kill their enemies.
The only real options I see are using a Sap all the time or taking that hefty -4 penalty all the time. Ideally you would alternate between the two to maximize your chances of being successful, but it's a big hassle to do all that. One could argue that to take that path a Paladin should be willing to make such sacrifices, but that's not the point here.
The point is, why is a largely inferior way of dealing damage to enemies so much harder to execute for most characters?
Can someone help me out here, explain to me why a rule simply letting characters deal lethal or non-lethal damage at will would be unbalancing (if it would be), and whether or not the following feat is balanced.
Benefit: Through your combat training, you have learned to focus on dealing non-lethal damage with your weapons, despite their deadly nature. Whenever you make an attack with any weapon you are proficient with, you may elect to deal non-lethal damage without the usual -4 penalty.
Normal: You take a -4 penalty to all attack rolls when attempting to deal non-lethal damage with a weapon not designed for it.
Or you could take bludgeoner.
Benefit: You take no penalty on attack rolls for using a lethal bludgeoning weapon to deal nonlethal damage.
It's using a weapon in an unintended way. It's much harder to not inflict grievous wounds on someone when you swing a sharp blade at them. In real life outside of using sedatives, any other way of putting someone out carries the risk of killing them.
It's not about the balance, it about the realism.
Personally I think the feat is perfectly fine balance wise.
Also see improved unarmed strike; I've known some players that have used it to avoid AoO and still use it non-lethal on the people they want to keep alive.
It is difficult to attack someone with a weapon designed to kill, and not kill them. That is why. When attacking to kill you are most likely willing to get the strikes in where ever you can. When fighting to not kill the attacks would have to be carefully placed.
See if your DM will work with you on using spells like sleep, hold person, hold monster or similar ways to incapacitate an enemy without killing them.