Not surprised at all. If I were Apple, I'd want to be in control of my end users' security. Message encryption through Apple servers is something Apple can protect and secure, instead of relying on a third party service. Let's not forget that iChat/AIM services are archaic; it's time to move on to bigger and better. ;)
Been waiting a long time for this, but I will say it would be nice if Messages/iCloud/FaceTime were a bit more ironed out before the move was made. It sure seemed like a lot of users held onto iChat/AIM because Messages wouldn't function properly. However, it seems resolved for the most part.
Here's to moving forward.