He will be. Give him time to adjust. Just look at Nowitzki's rookie season. People in Milwaukee were rubbing their hands for trading picks with Dallas and drafting Tractor Traylor.
You're really on the Dirk train but the truth is most guys are out of the league in 4 yrs even first round picks like Nits. Dirk was a once in a lifetime player. Not sure what Nits upside is but I doubt its as high as Nowitski.