EDIT: Done some research and Morello posted this
"We're doing some minor changes next patch. We -won't- be giving Nasus a gap-closer, but doing some Wither changes and Q base-vs-farm.
We decided against capping the Q, based on feedback. Instead, we're going to make it give less per kill, but more base. The best-case/worst-case did need to be changed to get him to be good, generally, and since people didn't want the Q capped, this is the alternative."