Even though I don't own a house, I prefer the 2 weeks policy.
But when I did own a house (summer 2014) I went on constant holidays and could be offline for 5-14 days. If I get home after 7 days, I'd rather sleep than go online just to keep my house.
I guess you want it to be 1 week so more players lose their house, but truth is that the only one who'll lose their house, is the players that goes on a holiday. The other players (atm) login once a week just to keep their house (even though they may not play the game). 1 week wont change anything.
If you want players to lose their houses, best would be to higher the monthly rent. By doing so, they have to collect MDC etc, etc.
I can't say that MDC is hard to collect. But hopefully you get the point.