WEREWOLF
Creature Type humanoid, beast, and shapechanger.
Ability Score Increase +2.
Size Medium.
Speed 30.
Common Language.
Other Language: Wolf Rapport (two-way communication of only simple animalistic concepts telepathically with werewolves, wolves, and dogs, within 30 feet, that can serve as part of Animal Handling checks, enchantment spells, or similar, if the communication is simple).
(Feat + Trait: totaling 10 points)
Werewolf
(4½ points)
Wolf Senses. Advantage to Perception checks relying on hearing and scent.
(2½ points)
Wolf Shape. You know the Wolf Shape spell (see below), and can cast it innately without spell component once per long rest; at character creation, choose its spellcasting ability, class, and power source: primal, psionic, arcane, or divine.
(3 points)
Damage Immunity. When you cast the Wolf Shape spell innately, the target gains resistance to non-silvered, nonmagical, slashing damage for 10 minutes, if remaining in wolf and hybrid forms.
At Higher Levels. At level 4, this resistance also extends to bludgeoning damage, and at level 8, to piercing damage. At level 12, this resistance becomes immunity to non-silvered, nonmagical, slashing, bludgeoning, and piercing damage. At level 16, the immunity endures as long as the spell is in effect, and whenever in wolf and hybrid forms.
WOLF SHAPE
Slot-2 transmutation
Casting Time: 1 minute
Range: 10 feet (one willing humanoid target)
Components: none
Duration: upto the end of next long rest, or until dispelled
Your mind visualizes your self-identity as a wolf. Then your physical body destabilizes under the influence of this mental shape.
While in Wolf Shape, you can shift fluidly between the forms of wolf, hybrid, and your normal humanoid. The hybrid can be any combination from a bipedal wolf to a humanoid with fangs, claws, and subtle lupine features. Every transformational shift takes 1 minute to complete − even when reverting to the humanoid form after the spell ends. Any equipment falls to the ground during a shift.
You retain the abilities and features of your character, except when the form impedes, such as the wolf maw unable to speak and the wolf paws unable to use various equipment. The wolf cannot wear the humanoid clothing and gear, but you can choose a form for the hybrid that can.
Normally, the shift into each new form is incomplete, such as the wolf form having human eyes, or the humanoid form retaining a wolf tail or wolf shaped ears or fur instead of hair (players choice). You can make an Animal Handling check versus an observers Animal Handling check, to pass as a true beast or a true humanoid. You can cast this spell when you arise from a long rest, thereby remain in Wolf Shape indefinitely.
In the wolf and hybrid forms, you can see in moon light as if bright light. The fur grants Base AC 11 natural armor plus any Dexterity and other applicable bonuses. The bite and claw attacks are natural weapons, that count as magical weapons, and that are finesse, light, and, while in hybrid form, suitable for the bonus action for a two weapon attack.
• Wolf Form: Medium, Base AC 11 (natural armor), Speed 40, bite 1d8 pierce, if hit, bonus action to Grapple.
• Hybrid Form: Medium, Base AC 11 (natural armor), bite 1d8 pierce and claw 1d8 slash, using a bonus action for the second attack.
At Higher Slots. When you cast this spell using a spell slot of 2 or higher, the casting time and each shift require 1 action, rather than 1 minute. Additionally, you gain 1d8 temporary hit points and AC +1, for each slot above 1.
Notes
I am curious about what a playable Werewolf looks like. The essence of it is one specific Alternate Form, in this case a Wolf. The complication is, there is a medial Hybrid Form in between. This Hybrid Form is fluid able to appear anywhere between Humanoid and Wolf, such as a bipedal Wolf or a Humanoid with claws.
A simple way is to create a spell, and have the feat grant the spell. Here, the new spell "Wolf Shape" is somewhere around a good slot-2 spell. Besides the vivid flavor, the main mechanical advantage is access to a 1d8 offhand weapon (claw or bite) that counts as a magical weapon. There is effectively a natural armor AC +1 while wolf or hybrid. The wolf form has speed 40, but then loses hands and speech.
Separate from the spell, I consider the advantage to Perception to be powerful, and the sense of smell and hearing useful. 4½ points, but not 6 points since without visual advantage.
I am experimenting to make Damage Resistance balanced. This isnt written in stone yet. It might be ok, or it might be too powerful.
There is the trope of the Werewolf losing ones mind to the beast entirely, and its magical ferocity. But this is for a playable character and doesnt go there. If interesting, a feral Werewolf is an NPC that gains one Difficult Animal Handling skill check per full moon until success, in order to finally overcome the instinctive urges and regain ones mind, and become a playable character while in Wolf Shape.
Special. Consult with the DM if the lycanthrope of this player Werewolf is contagious. (If so, when a target wounded from a bite reduces to 0 hit points, target must have a DC 12 Con save, or be cursed with lycanthropy.) In any case, the player character has no special influence over any new Werewolves that might emerge. All new Werewolves are feral Unaligned NPCs but ferocious, aggressive, and dangerous, until learning how to master their animal nature. Each new moon allows one Difficult Animal Handling check, until success to gain control over the wolven form.