I'd be fine with one service account own one house per server.

Raising prices is a fake suggestion. It's not only impractically to say the least, but it only enhances the problem if actually implemented. Selling houses isn't done with a markup of an X amount of gil, it's done with a 2X or 3X times amount of gil or similar. It's a suggestion made to enhance the profits of those who are abusing the system currently. Same with the suggestion for a 5 day auto demolition timer, it merely gives these people more opportunity to acquire more real estate.

These suggestions should be taken as the opposite of seriously. They are designed to exploit the player base.

The specific problem we run into with limited player housing is with FC housing. If the FC lead drops and your character is forced into the leadership position, you effectively own the house. What needs to be addressed here is this specific situation. If we can knock this out of the way with some sort of change or compromise, then SE should theoretically be able to impose limitations without much negative feedback, aside from those few players who are currently exploiting the system.