Some thoughts on the Favored Enemy portions of Deepwood Stalker...
Favored Defense
Combine the tier 1 and tier 2 choices into a single Favored Defense that grants the AC and Save bonuses together. For full rangers the two options are fairly dubious choices anyway. This will never be useful enough for a ranger splash to even consider taking, but for a ranger with 4 or 5 FEs and a high AC it may be a decent choice instead of just filler to get to higher tiers.
Favored Accuracy & Damage
The attack and damage bonuses are decent, but could stand to be shifted down a tier. This still doesn't make it worthwhile for most splashes, but it does bring the total investment required for +3/+3 vs a subset of enemies to a more reasonable 16 APs instead of 26.
Extra Favored Enemy
Seems ideal on this tree and is a decent investment since it adds both damage and more things for your bonuses to work against, but it feels pretty bland for a top tier ability.
To spice it up, add an exclusive option against it so you can either generalize or specialize. Here is an example.
Enemy Specialization
Choose one of your existing favored enemies to receive additional bonuses. Training Enemy Specialization locks out Extra Favored Enemy.
Animal: Weapons you equip gain Animal Bane. Your animal empathy now recharges at a rate of 1 per 90 seconds. You may expend a use of Animal Empathy to scare an animal to death on a failed save. Additionally you are immune to non-magical diseases typically carried by animals.
Dragon: Weapons you equip gain Dragon Bane. Your familiarity with dragons gives you a +8 bonus to saves vs breath weapons, wing buffet attacks, and tail slaps (of all creatures, not just dragons). Additionally, you are immune to Shock and Awe.
Giant: Weapons you equip gain Giant Bane. Enemies struck by your weapons lose any Fast Healing or Regeneration abilities permanently. Additionally, you gain a +8 bonus to saves vs knockdown.
Ooze: Weapons you equip gain Ooze Bane. Your equipped gear is immune to acid and rust damage. Whenever an enemy would be split by one of your attacks, it dies instead. Additionally your boots are treated to grant immunity to slippery surfaces.
Reptilian: Weapons you equip gain Reptilian Bane. Your weapons gain the crippling property, making it harder for kobolds to climb up the walls and avoid your attacks. In addition, Kobolds will always hate you and attempt to melee with you first.