A stab at an essentials style seeker.

Keep armor/HP/healing surge/defences/etc the same.

First, some baseline RBAs:

Seeker's Arrow
Ranged Weapon + At-Will Primal Attack
Requires: Projectile Weapon
Attack: Wisdom vs AC
Hit: [W]+Dex
Special: Seeker's Arrow counts as a Ranged Basic Attack

Seeker's Throw
Ranged Weapon + At-Will Primal Attack
Requires: Thrown Weapon
Attack: Wisdom vs AC
Hit: [W]+Str
Special: Seeker's Throw counts as a Ranged Basic Attack

All seekers get both powers. The use of a different stat-for-damage is intentional.

Next, maybe a stance like mechanic for at-will replacements. Ie:

Elemental Aura
Minor Action + At-Will Primal Utility
Aura 1
Special: Select Fire, Cold, Lightning or Thunder when you activate the aura. This power gains that damage type and keyword.
Effect: Enemies who attack or end their turn within the aura take Wisdom+1/2 level damage. If you hit a target with a ranged basic attack all enemies in a close burst 2 from the target take Wisdom+1/2 level damage. A creature can take this damage at most once per turn.

A psychic aura (howls of spirits?) A forced movement aura (wind?) A protective aura?

Next, riders. These act as modifiers to your ranged basic attacks, sort of like how slayer's encounter powers do.

Meh, not fun enough.