Facebook has the destination site they want. You are not going to help them build it. The second you become even marginally inconvenient they will pay attention to everything you do and shut down your app without a second thought if they think it's in their interests.
They did it to Slide (Top Friends) and Zynga (FishVille). They will do it to you as soon as you even approach that level of success.
This isn't a condemnation. It's just the cost of doing business on the Facebook Platform. I like the fact that Facebook's motives are so transparent because (unlike Google) it makes it easy to anticipate how they'll react. They're completely rational and self-interested (for the most part -- the original live feed was a mistake, as was Beacon).
It's clear that Facebook has cared more about Connect than the Platform for a long time; at least a year. This latest change just formalizes it and finally incentivizes developers to build on Connect rather than the Platform.
See Scott Rafer's presentation "The Facebook Platform is Dead" from last October, where he predicts all of this.
But keep in mind, once Facebook has the Network they want, they're going to do the exact same thing they did on the Platform.
You are not safe there. If you're building on Facebook Connect you need an escape plan from Day 1.
Facebook giveth and Facebook taketh, and they will take.