Barbarian: I like it. I really like the feel of a lycan or vampire. My only real complaint is the first ability at 3. I'd like to see you get both the bite and claws when you transform, and not get the tail. This does limit the general beast option more, but improves the lycan or vampire aspect. 2 Bite attacks, 2 (3) claw attacks, 1 bite, 1 (2) claw attacks. From a damage standpoint I don't think that sounds unreasonable and really reinforces the bestial nature of attacking with tooth and nail. The tail, while useful, goes in a different direction.
Monk: Looks good overall. Not really something I would play personally, but an interesting concept. The Noxious Aura reads a bit too much as bad body odor to me.
Paladin: Spells, awesome. Worthwhile additions that mean you just won't be using them all to smite. Channel Divinity gives some good options that make it worth using. The aura is very thematic. I like the Vigilant Rebuke, although I'm not really sure that it fits the Watcher theme as much. The Capstone seems like one of the weaker capstones, but being a bonus action helps to balance it. It makes me wish the other capstones were bonus actions, even if their power decreased.
Warlock: A good concept, but the powers are all over the place. I just don't understand how the tethered creature correlates to a Genie. Genie's Entertainment is the only one that seems to fit. Collector's Call, while useful, has a clunky mechanic. It encourages multiclassing for expertise and punishes using items like Rod of the Pact Keeper that increase your spell DC.