Has anyone got anywhere near this with 4 players?
the set-up just seems ridiculous:
Threat 8 location in the staging area, immune to player card effects (so you can't ignore it's threat, reduce the threat, travel to it, or explore it.)
8 Cards coming off the encounter deck per turn
every time you lose a riddle Bilbo takes minimum one damage, which you can't heal as he also is immune to player card effects. Likewise, you can't snare or otherwise kill Gollum due to the immune to card effects.
The only really doable way to deal with riddles seems to be building monosphere decks, ideally with little variation in card cost and/or very heavy on a single card type. Evidently, what they gain from that build they're going to lose in general game-play utility.