The previous lottery thread i saw was a lottery to get a house in new zones which is what people hated.
being able to see a demo zone and put down your payment for a chance at getting it(or your money back) when it pops up seems totally fine to me.
only complication i see is i think relocation bypasses the demo mechanic which technically isn't any different than now but might feel like kind of a jerk move though i suppose with random demo times if everyone just got their money mailed back no one would even know...