Dennard is undeniably better than Kevin Peterson. Now, from looking at counting stats, he isn't better than Kirkpatrick, but my eyeballs told me that Kirkpatrick wasn't very good last season.
I think at worse, the starters aren't quite as good overall, but the depth IS better. Over a 17 game season, sometimes depth wins out. Look at what happened with the safety position last year where depth was tested and the end of the roster guys were so bad, the Cardinals were hemorrhaging yards until better players got healthy.