The funny thing is there would be an easy, and thematic, way to fix the Denethor's ally problem. Just add "When Denethor enters play, search your deck for 1 Gondor card and add it to your hand." This could of course bring your Steward of Gondor, for instance. Or even better perhaps "After you play Denethor from your hand, search your deck for 1 title card and add it to your hand." Which could bring either Steward of Gondor or Lord of Morthond. This addition would make the card intriguing for me, and an obvious inclusion (perhaps even more than a single copy), and would stop me from ranting about the card.
Cool idea! Shame designers, poor useless Denethor. But art is cool anyway!