Yes, but speaking from experience, that change resulted in a huge improvement in call quality. The P2P architecture is nice but leaves you at the mercy of your nearest node's internet connection and usage.
Not my experience. Having network issues all the time.
They did so because it was hard to do P2P for Skype on phones.
I figured that was just a figleaf and that the real reason was that this made it easier to intercept the traffic.