OK, I know ideas like adding more hooks, more locations, or putting ex-player's houses back up for sale are rife with complexities.
But here's something very simple I'd like to see. Invitations. It wouldn't be earth-shaking, but would be an easy way to perk up housing events and activities.
Sold from vendors, maybe 10 or 20 silver each. Once in your inventory, click it (have to be at a mailbox) and you can specify the receiver and the time (up to a week from present) they are invited to arrive. The receiver gets it, and can, at the specified time (or up to 30 minutes after) use it as a one time transport to the sender's house. They go away if not used in that time frame.
This would make it much easier to schedule events at your house--an invitation, reminder and a port all in one. Or just to have a few friends pop by to see your new decorations without them having to take 10+ minutes to travel and figure out how to get to your neighborhood and -then- have to make their way back to their original location afterwards.
Invitations would share a 1 hour timeout--can't use more than one, say, an hour to port (to prevent any gaming of it as a cheap transport mechanism).
After using the invitation--it doesn't disappear, but becomes a "Party's over" port that returns you to your original location--then disappears. This would make it so much easier for people to visit your home without it being a hassle.
I could see "invite kits" sold as well. For 100 silver, a group invite to your house that goes out to all kin members. Or special "Kin-house" invites that invite non-kin members to your kin house. Maybe even "party packs" for sale in the Lotro Store with say 50 invites, 10 fireworks, balloons, beer, wine..that kind of thing.
I can't imagine this would be hard to do or has much in the way of balance issues to consider. It's not much, but would make housing a bit more of an activity hub, and make it much easier to show off all the hard work you put into decorating your house to your friends.