It could be that the devs are trying to open up as much house space as they possibly can before starting Return To Britannia, that way all the new players would be able to easily find a house and be more likely to keep playing.
There's been a lot of similar comments so far in this thread, with people also saying how the changes aren't all bad. To that point - "randomizing" the idoc system has its pros, and its cons, but let's just say hypothetically that the pros win out and that every single poster here becomes in agreement that "randomizing" things is the way to go, it's still NOT the point of this topic.
The point of this topic is that the existing system is broken, and for some reason no one is acknowledging/responding to it officially. Houses have been at the CORE of uo since the start, and you simply cannot mess with people's houses without warning of changes. It's not like the change being discussed is how fast a Lich spawns in Deceit or how powerful that Lich is, where the worst case scenario is your character dies - the change here can mean you loose all of your belongings you've amassed over 15+ years of playing the game if your house decays unexpectedly.
If Devs wants to randomize idocs, than you post on uo.com "New Idoc rules. It's random". Some will be pissed, some will be happy, but at least we'd know it was intended and plan accordingly.
The sad thing is that its obvious this change was in NO WAY intended, as they never make such changes without warning. This is just someone on the UO team messing up big time, and UO's customer service team being so awesome that a few days later we've still received no official feedback and nothing has been fixed.