Josh Hylton writes for Bleeding Cool:
The more I hear about Scream 4, the more worried I become. I'm a big fan of the original trilogy, but it's hard to find anyone who thinks the third film really stands up to the two that came before it. In part, that's due to the substantially worse writing from Ehren Kruger, who fudged the clever horror parodies present in Kevin Williamson's scripts for the first two.
Sadly, it now appears confirmed that Williamson won't be back to write the fifth and sixth installments, should they happen. Shock Till You Drop is reporting that Dimension Films is on the lookout for a potential writer (though it's worth noting that this information appears to be from easily subverted industry tracking boards, which means this is not necessarily cold hard fact and should be taken strictly as rumor for now).
If Williamson's not on board, neither am I.
In regards to how Scream 4 will likely turn out, here's a quote from director Wes Craven, speaking to Total Film:
In some ways it's a Wes Craven film, and in a way it's not entirely, because it's not a script I have control of. Look, there was a bumpy period when things shifted over from Kevin to Ehren. I signed up to do a script by Kevin and unfortunately that didn't go all the way through the shooting.