If you really use Twitter or Facebook then you'd have those installed and launching one and going to post and update there isn't that much more than using what was in the notification center. Sure it's not as convenient, but at the same time not really that much worse. That said, would be nice to have it back for those who want it, but probably more like in control center rather than notification center.
It's less time consuming to swipe down and hit tap to tweet than it is to open the app, wait for it to load, then tweet/post.
But considering how much slower they made iOS7 it's no surprise this was done.