I don't think Oates was good because he kept overrating Parise's creativity. Parise is not the guy who'll "do something" with the puck and make a play. Putting him down below the goal line robbed him of his greatest PP assets in his deflections and rebounds.
Shaw, honestly, in my opinion, ran a pretty good powerplay, but the team was a total mess this year and so were both special teams groups. The Devils were 9th in shots per 60 minute of PP time this season, under Shaw. Prior to that, they were 25th (11-12), 16th (10-11), 17th (09-10). In 08-09 they were 3rd.
I'd love to see Brown brought in from the Canucks. He runs a similar system to Shaw but focuses a lot more on movement and rotation, and using that to find lanes for one-timers. He was on record this off-season as saying Vancouver's PP sucked this year because they had 5 left shots. He definitely won't have that problem here with Kovalchuk, Zidlicky, Zajac, and Clarkson to work with on two units.
Plus, if Oates, Shaw, and Brown all come through New Jersey without fixing the PP, I think then we can finally stop blaming coaching once and for all.