Favored Terrain: The Ranger is top warrior in their environment of origin, whatever the Player chooses that to be. Examples include (but are not limited to) Woodlands, Marshlands, Desert, Arctic/Tundra, Urban, etc...
This choice triggers a few things for the Ranger.
Natural Healing: All Rangers are very knowledgeable about the flora and fauna and are able to gather natural materials (plants, fungi, animal parts or fluids) to assist in Healing and first aid for her allies. With these materials available (either on the Ranger's person or able to be found in the immediate area), the Ranger is able to apply ONE additional HD (of the person being healed, not the Ranger's HD) during a long rest. Having or finding these materials should be assumed to be 100% while in the Ranger's Favored Terrain. Other terrains might require some searching (DM's call.).
- The Ranger receives a +2 applied toward skills/ability checks that are appropriate for their Favored Terrain (Swimming or Sailing for a ranger from the Coast, for example).
- Similarly, the Ranger knows how to maneuver particularly well in their chosen environment. All Rangers gain a +1 to their Attack rolls while fighting within their Favored Terrain.
- The Ranger gains an additional +1 to their Tracking rolls if in their Favored Terrain. They receive an additional +1 if what they are tracking is one of their selected Favored Quarry.
- Rangers receive a +2 bonus to all Stealth checks while within their Favored Terrain.
- The Ranger is able to select 2 types of creatures that were prevalent or recurring threats in their Favored Terrain. These creatures are the Ranger's "Favored Quarry". They are the greatest recurring and infamous threats to her lands and she has spent much time hunting and/or learning to fight them before setting off on the Adventurer's path. The Ranger gains a +2 to all damage rolls, regardless of weapon, against them. Examples/guidelines: A Ranger of Woodland Terrain might choose Orcs and Owlbears. A Ranger who favors/is from Mountain Terrain might choose Goblins and Ogres. A Ranger with Swamp Terrain favored might choose Lizardmen and Black Dragons.
Those abilities are too specific and have the same flaws of Rangers of the past. Favored Enemy/Environment works for only in the area or on the target chosen, forcing the DM to constantly use that enemy/environment. Even if the DM tell them of what the best choice is ahead of time, they are stuck with it.
A better way is to make the bonuses more broadly usable.
Forest Ranger
Can apply his Hunter's Quarry to Geographical Lore, Spot, and Stealth checks.
Can craft a Healer kit for half price
Ranged attacks ignore ACC bonus for half cover.
Always consider lightly obscured in an open natural environment and heavy obscured in light obscured natural environments.
Koboldhunter Ranger
Can apply his Hunter's Quarry to Find and Remove Tracks, Intimidate, Spot checks.
Can deploy a Hunter's trap as a action
+2 Ac when being attacked by more than 2 enemies
Can make one attack with a finesse weapon when making a Dodge action