I've been playing around with this deck for some time and have modified it heavily as I play. These three heroes work so well together that I keep coming back to them. I've tried dropping Glorfindel for Mablung and making it a bit more tactics-heavy, but I found the extra spirit hero to be much more successful. I also tried using the spirit version of Beregond (With Mablung), but found the attack power to be too light without Glorfindel. Cirdan is fantastic in a non-lore deck as he provides a lot of extra card draw. Glorfindel has his attachments because, really, he's just awesome at slaying stuff while questing simultaneousy. Beregond gets all of his toys for free, which frees his resources up for other handy items (or Gandalf).
For multiplayer, I drop the Harp and Spear in favor of the Rivendell Bow and some Northern Trackers. I also drop Unseen Strike and Galadhrim's Greeting for Behind Strong Walls and Desperate Defense. Feint has less utility because of immunity, but might be useful. Revealed in Wrath may be a great card in some quests, but I have yet to absolutely need it.
Quick note on Blood of Numenor: I rarely need it, but when I inevitably get some attachment hate, I treat it's text box as "Discard to Cancel the Effects of That Attachment Discarding Shadow Card".