I think Dixon consciously wanted to interpret NW as DC's version of a powerless Spider-Man/Daredevil. Not invincible, all the quips, sometimes a reluctant hero and cheerier. I agree that Dixon's main problem was in creating any great rogues, but ask yourself, how many other writers are able to do it? Like creating a new hero, all the good (or bad in this case) ideas are taken.
Also, you have to cut a guy a break when other writers take characters and devalue them in a different book. That's out of Dixon's control. Bane and KGBeast were both completely bad-@$$ when they were introduced, meant to be the equivalent to Batman, only evil. Look what was done to them.
Dick shouldn't be as good as Batman, but he doesn't need to be. He brings a different attitude and outlook on life. Which is refreshing to Mr. Grim n' Gritty all the time. He's also got a slightly different set of baggage than Bruce. Sometimes I think that biggest shadow Dick has to get out from under isn't Bruce's, but the fans.