Very nice. I think warlocks should always have some kind of ambition driving them, at least if you do a typical warlock/patron relationship. Bonus points if you go pact of the Chain (sprite) and fluff it as looking like a little angel over their shoulder.

Personally a fan of having the patrons personalities come alive in campaigns. Broken pacts often mean ends of powers or more serious consequences. Love having larger things afoot. Also really love dualities with warlocks, powers meaning one thing then powers doing another like wild magic...