I am aware the guild-hall is our "housing-system", however unless it was my own guild - I can't get myslef to get invested into spending time and resources, just to see it eventually fall apart or to be kicked because of unavoidable inactivity.

If we could simply "bring our rooms with us" that might change for me.

The "private rooms" would be only accesible if you are member of a guild and that guild was not in default.
They would be accesed from within the guildhall, similar to the entering the private training hall. Let's call that section "living quarters".
A drop down menu would give you acces to either your own or other members "private rooms", if you are invited.

That way members of a guild would be more inclined to pay for the guilds sustention if they want to acces their "private room".

The room would give you access to a small area that you could customize to your liking, invite friends to and even set as a replacement for the Ready-Room screen. It should not replace functional systems within the guild-hall like the training room.

As for the specific decorations and/or interactive items, they are open to debate.

The catch is you pay and unlock everything within that room with prestige points and ranks.
That's right, let's make it a currency and a possible crown sink.

The higher your prestige rank is, the bigger the room gets, but buying furniture/items is done so with prestige points.
If you drop a rank, your room gets smaller and the furniture goes back into an inventory.
There could even be a small prestige-fee to maintain the room, past a certain rank. (To keep things moving.)

Those supply packs in the AH would make a pretty crownsink if more players were interested in adquiring more prestige more frecuently.

Of course exact prices, prestige-mission-payouts, etc. would have to be decided/adjusted.