When playing Progression style, Denethor is always in our hero pool (wielding A Burning Brand as soon as it unlocks in quest five) at least until Elrond shows up near the end of the second cycle. (After that Beravor and Elrond+Vilya tend to get picked first.) Matrosh already noted that stacking Unexpected Courage on Denethor is great (I agree), but something to consider is not to only bury scary cards. Instead, let Henamarth Riversong (activated after you've used all your Denethor actions for the round) cover your early game spying needs while Denethor studies the enemy's long term plans! Have Denethor bury every card that isn't a victory or critical quest card (and leave each buried one face up since it's now a known card unless the deck gets shuffled) until you eventually know every remaining encounter card and can strategically pick which ones come when. Obviously you don't want to do this on quests where the encounter deck can reshuffle itself early or unexpectedly, and you also don't want to do it when you or your team are using something like Mariner's Compass.

Overall, Denethor is top notch when you only have the Core set. Once you get past the first few cycles and unlock more choices, he's still a viable choice depending on your deck build.

I wish they had made this more like Secret Vigil so it scaled with player count. As is, I frequently end up with this card in my sideboard having not quite made the cut down to 50 cards. Elrond's Counsel is superior as long as you meet the Noldor and color requirements. For solo play without access to blue or red I suppose this might make the cut. (I don't know that I'd ever play purple/green as a solo deck, though.)

Nice card (as NoSoup4you already noted), but why isn't it a Trap (vs Condition) or an Event (vs Attachment)? See examples below. The flavor text seems to clearly show that the rangers are lying in wait (to keep the Shire safe), and the mechanic of LOTR LCG for the rangers dealing with enemies is Traps. I don't see how Secret Vigil became a Condition Attachment.

Trap: Play Secret Vigil into the staging area unattached. If unattached, attach Secret Vigil to the next eligible enemy that enters the staging area. Limit 1 per enemy. (Same effect in other respects. Compare to Ranger Spikes.)

Event: Choose an enemy in play. That enemy gets -1 this round. When that enemy is destroyed this round, reduce each player's threat by that enemy's printed .

Imladris Stargazer, Zigil Miner, and Hidden Cache are insanely good together. If you're doing that, it often makes sense to include Ered Luin Miner too. It's obviously great to trash extra copies of unique cards like Steward of Gondor (or whatever it might be in your favored deck). If Dáin Ironfoot is at the table, then Zigil Miner is a fine questing or attacking dwarf even without mining. This has been one of my favorite cards from when I first played it all the way until now roughly a decade later.

It seems strange to me that no one is gushing praise for this card. First, it seems obvious this card was made for playing Outlands characters and is quite effective for doing so. For example, Hirluin the Fair can play Ethir Swordsman and draw a card from Lord of Morthond. This is great. Second, it is perhaps even more potent with Silvan tricks that are already quite powerful without this boost. Any mono-leadership deck is likely to be running three copies of the much-praised Steward of Gondor, whose resource generation has warped the entire game from day one. Let's say Thranduil becomes Steward of Gondor (thus gaining the Gondor trait) followed by Lord of Morthond. The Elvenking becomes recurring card draw in addition to its already useful function, Feigned Voices now replaces itself when Galion is replayed for free with Thranduil's combat ability, and Host of Galadhrim becomes the best card-draw event in the game in addition to its other benefits. I suppose one could even run both Outlands and Silvan in the same deck with Hirluin the Fair, Thranduil, and Celeborn leading the way to a full four-color army of "cantrip" allies?