He's the protector of the Omniverse, and his powers are based on willpower....uh what? Is this just a straight rip-off?

When/Where was this?

@ArturoCalaKayVee: Apparently his powers changed when Merlyn resurrected him during the Skrull invasion.

His confidence. Not his willpower. And I have heard nothing of him being a protector

The Captain Britain Corps has existed since 1984, with the same purpose of defending the multiverse, so it's hardly a new development.
The term Omniverse is often used wrong by marvel.

He is a protector of Earth 616, and the Corps as as whole are seen to protect the Marvel Multiverse, as is their purpose created by Merlyn and Roma. Originally each 'Earth' possessed a Captain Britain that would protect that Reality, however, after Albion's rampage and the cull enacted by The Fury and Mad Jim Jaspers, there is only 1 Corps Member per 10 Realities according to Brian in Uncanny X-Force. However, this isn't a new thing, this is been the status quo since Alan Moore's tenor with the Character back in the 80s.

The Confidence thing is similar to Gladiator's power, and moreover, considering he's a brick archetype rather than an Energy Manipulator I'd say the only real similarity to the GLC is that he's a member of the CBC. (Captain Britain Corps).