1. Introduce housing but MERGE it with transportation options to additional raid/challenge/assault-style quests. I would take the base castle from the quest "Storm the Beaches" and turn it up ten notches. Make it a difficult castle to storm for Epic/capped players. Bump the archers w/ Archer's Focus (or Manyshot) and make the Ballistae into Catapults that throw boulders from the "Fury of the Wild" ED. You could only access these world events from your house, (alternatively, you could make them accessible from guild ships with the right amenities). If from your house, you have to inform the steward you will be leaving to fight in the *insert name of world event here* and in order to anchor your house from being pulled apart by the teleportative forces, (think: Acquisitions Incorporated) you must leave him some astral shards to bind your house to the astral plane. Alternatively, it could require a small amount of AS to bind your house for a set period of time so you could become involved with as many world events as you want, during that period. The world events should feel like halfway between a challenge and a raid, ideally. The loot/modules should require both Cannith AND Eveningstar Challenge ingredients but with the modules requiring added cost and difficulty to acquire. I am thinking something like challenge items might require certain modules to be upgraded OR they might require Commendations/Universal Challenge Tokens or Epic Tokens to unlock additional tiers.
2. Introduce companions into roles around the house. I want my Mephit to be my librarian (with according bonuses/penalties). The Earth Elemental gets to be the cook and make me Tasty Ham because he knows all about Stone Soup. The Kobold gets to send to me world events in the Sewers because, he remembers Waterworks. While the Shadow Gargoyle gets to send me to the Mabar end fight with a little twist OR perhaps to a Shadowfell Conspiracy themed event. The Tressym would make an excellent butler (especially the tuxedo Tressym). Pseudodragons know a way to enter the Truthful ones bed-chamber via Khyber. The owlbear companion would make a fine feather-duster and perhaps assist in the library (even promoted to head libarian!). In order to "set" a companion on one of these slots, it should require something similar to slotting an amenity is to a airship. I would think that some slots could be filled by any of the companions but would give different effects or bonuses depending on the action performed (entering instance/crafting/tome activation).
I would like Housing to give us access to more Raid-like events in the future. That way, we choose Housing now, but we use it to access more raid/challenge-like events from one single location. You should be able to start on your guild ship and then port to whoever's house is "anchored" (astral shards) for that time-period. Some events might require that more than ONE house is linked to the astral plane. Or perhaps it requires Shavarath War Trophies to bind your house to Shavarath, or for instance, Lammania Lily Petals to bind your house to Lammania.
3. I would make Universal Challenge Tokens BTA. Then, I would introduce them into the crafting system to make scrolls/wands/rods and other unique items. This could even be linked with player housing and a special altar or crafting station. Universal Tokens could be another currency. All Epic tomes (+6 or above) might require you be in a library to use (one such library might be in player-housing, while another might be located in an adventure pack) We could even use Universal Challenge tokens to actually read the tome (give us an excerpt). It would be a great cross-promotion with some of the new Forgotten Realm book series/DnD movies.
In addition, I would like to be able to use Universal Challenge tokens to attempt to read a Nether Scroll, and make the results AWESOME!
Either way, player-housing needs to be dynamic and functional, Turbine certainly has the ability to deliver on both.