To answer Quartz:
The Unearthed Arcana (not the Arcana Unearthed, mind you -- 2 different books) proposes a variant called the Urban Ranger. Rangers loses some "wild" abilities, spell list is different... but no need for all that.
Just the one main idea here is important:
Favored Enemy can be a group or organisation instead.
This opens the door to a lot of possibilities.
Even the core book suggests that some Favored Enemies groupings are "too big" and must be divided into subgroups. Favored Enemy (Humanoids), according to core rules, is "too big an advantage", so the ranger must choose a Favored Enemy Humanoids subgrouping, for example (Humans), (Goblinoids), (Dwarves), etc... Each taken separately.
So Favored Humanoids(Humans) is too powerful in your campaign?
Go one step further. The player must choose a sub-sub group.
Choose your logic, or choose both logics:
- Some humans cultures have wildly varying fighting techniques, so different favored enemy selections are appropriate for them.
- The Ranger's "hatred for these enemies" targets only some part of the human race.
The same way, if some Favored Enemy selections are too weak in your campaign because those monsters are way too rare, just fuse several FavoredEnemy groupings into a single super-group!
So, what do you have? Rare combats, and mostly with humans, or at least humanoids, right? With other Monsters being really rare.
So in your campaign you could have the following Favored Enemies selections:
* Orcs-n-Gobs (including gnolls and bugbears, those humanoid baddies, really, who can tell em apart? they're all freakin savage monsters on two legs)
* Underdark (Dwarves, some gnomes, undermountain creatures, slimes, drow, etc. -- anything from "dark places")
* Lizards (Dragons, animal lizards, lizardfolk, anything reptilian)
* Faeriefolk (Elves, some gnomes, all that woodland fairy stuff)
* Humans - Blood Cult (those vicious human sacrificers and necromancers)
* Humans - Barbarians
* Humanoids - Spellcasters
etc. Make your own list!
It does not need to be exhaustive.
The important thing is to make sure the ability will encompass a group of foes big enough to see some use during an adventure, in most adventure, and a lot of use in a minority of adventures, but not so broad that it will definitely see use every other fight in nearly all adventures.
The best is to let the player choose what he wants and you limit the scope. Does he see his Favored enemy ability as knowing a foes's fighting technique, or does it represent a dislike of a specific enemy?
If spellcasters are really rare in your campaign, Spellcasters is a valid favored enemy choice. If they are so plentiful that there are actually restaurants serving Heroes Feasts for breakfast, the Red Cult is an important recurring enemy (about one adventure out of every two centering on these villains) and has all types of classes in it, wizards, fighters, rogues and evil clerics, not just clerics, then maybe "Humanoids - Humans - Priests of the Red Cult" becomes a valid choice.
Exemple: Skill based:
Humans - Armymen (any well-organised and strructured military unit fighting in groups)
So it would cover the Steel Claw Orcs, which are the *only* orcs using an "elite" military. It wouldn't cover the Steel Claw leadersm unless they too are part of the same military training and fight in the ranks with the other soldiers. So it would probably cover the orc sergeant, NOT the chieftain ands his personal bodyguards, which use a different fighting style, and *not* "conventional military formation" techniques. Even a common soldier would grant the bonus only when confronted in group. Take the guard alone, he's not in an army unit anymore, and fights differently. But as soon as at least three soldiers gang up on you, bingo, here's the bonus!
Humans - Baron Belzebaal's Black Barony
Here, everybody from that barony that works for Baron Belzebaal is included. The ranger will even gain the bonus against innocent people (everybody rom that baronny is evil and should die!) -- possibly great roleplay opportunities here (or at least simply great psychotic fun, not my cup of tea but its a possibility).
So you see, there is some overlap:
Both last suggestions would include Baron Belzebaal's army. But the first would not include the baron himself, while the other would not include other armies from other lands.
The second version is actually potentially the most fun to use, but also the most dangerous in play for game balance.
For example, if you decide that the main focus of the game is fighting, adventure after adventure, the Baron and his evil army, foiling the baron's plans, etc., then you should actually split that subgroup again. On the opposite side, if the focus of the campaign completely moves away from the baron, then the player will never get to use his ability, which is bad. For example, if that baronny gets fully destroyed, the baron is dead and ewson't come back, etc., then the player should be allowed to chose something else after some "retraining", or at least some time, has elapsed.
What you want to avoid those two extremes: Feat used all the time, and feat rarely used.
So make sure you "'format" the feat'' wording clearly so that the way the player will use it will fit the frequency you want (you know your campaign setup and what foes any particular organization is made mainly of).
This is cool because it also forces you to make your adventures more varied.
Like: "Okay, the ranger is good vs the baron, is servants, and his army. Anything "baron" gets the bonus? Damn, the ranger will get the bonus for this ENTIRE story arc? Bad. So maybe the servants priest should summon monsters, and the army uses war beasts, and the like. And against THOSE the ranger doesn't get his Humanoids (Baron's Guys) bonus. And maybe the baron hirs barbarian from the north, they serve the baron but they are not really '"devoted" to him, so no bonus against these guys either... The player will still get to use his bonus in every single one of these games, just not all the time and potentially against all foes... If he plays intelligently, he'll concentrate on the foes he does have a bonus against, and will get to use his bonus neartly every fight, but if he plays stupid, he'll attack the enemies harassing him that he doesn't get a bonus against, and will get to use his bonus only half as often if not less".
Personnally, when in doubt, I'd make the categories sufficiently large, and let the ranger use the bonus as often as possible. It's just up to +2 to +8 damage after all. When the 10th level wizard blasts 10 soldiers dealing over 200 damage to them, that whopping +8 suddenly seems quite meager...
Pax