The purpose of this deck is to generate resources and then distribute them to the other players.
The key synergies are the Gondor-resource generation (Allies, Steward etc), Gondor-swarm (Leadership Boromir, Ally Faramir, Visionary Leadership etc) with cards that allow transfer of Resources to other Heroes (Parting Gifts, Hero Denethor, Errand-rider).
It is a multiplayer deck that benefits from three or more players so that they can pick up the questing and combat phases, but it will hold its own with Allies such as Warden of Helm's Deep and the natural Willpower boost of Visionary Leadership. Strength of Arms can benefit a four-player party substantially and Campfire Tales becomes more efficient the more players are at the table.
Heir of Mardil and Steward of Gondor do not have to be played on the decks heroes; as the aim of the Bank is to distribute resources a Steward on to Erestor (for instance) is just fulfilling that goal in a particularly fixed way. That being said, Heir of Mardil onto Boromir, and then a resource from Denethor in the combat phase to stand-him can be a very useful readying trick.
I have considered dropping Anborn and the single Rod Steward for three Sneak Attack, and may well move that way after more significant testing.