Thought about trying to build a 4 player deck that can reliably defend against most threats. While the deck doesn't have the sheer defensive stats some other decks can put up, it combines some relatively sturdy characters with good canceling of shadow effects and decently reliable, if conditional, healing.
Basic idea is just to stack Signals on the heroes to buff up their stats, then repeatably block enemies. Aragorn and Halbarad can reliably quest while still being defenders(making good use of the Quests), while any of them paired with a Destrier provides repeated blocking. With a few Warnings to get their armor up and a Remedy to bounce around to keep each other healed, they should be able to block most run of the mill enemies. Indeed, one of the ideas behind the deck is to simply hold as many enemies engaged with you as possible, freeing up the other decks to commit to questing and dealing with other threats. Anchor Watch and Terrible to Behold can deal with the bigger enemies that come by, giving you more options than simply blocking with an ally to tank the hit.
Sneak Attack with Gandalf is a fairly simple combo, but the Watchmen don't mind the effect either. Valiant Sacrifice can trigger off Sneak Attack as well, producing quite a bit of burst draw. Erestor provides fairly straightforward card draw to find the pieces of this deck, and helps with all the duplicates. Sword Thain can make Gimili forth hero who both quests and blocks, as well as easing the resource burden of Remedy, but Erestor is a fine choice for it as well, and helps to keep him alive.
One of the secondary keys to the deck is resource generation, both to play the semi expensive cards and to repeatably trigger Remedy. I wanted to avoid limited resource gain to free it up for other players. Ideally, Halbarad gets Rune Master, as he's likely to get the most Signals, Erkenbrand gets Day's Rising, letting him pick up extra resources from his second block or when a shadow card doesn't trigger, and Aragorn hopefully benefits from the Mardil + Wisdom combo.
Deck is ultimately still a work in progress, however, and I'm curious to see how it does.