None of these players were what they are now when Green was coaching, some of that's on him (not using them on the PK) but some of it also comes down to each player having taken steps forward.
He was an interim guy in Jersey, but he was also thought of well enough to have an assistant/associate role in the first place. Green was never likely to permanently hold on to the Devil's head coaching role, they view themselves as a playoff team and likely want someone more experienced like Berube. Ottawa has talent, but I can understand why a head coaching candidate with more options might not want to take on the pressure of getting Ottawa back to the playoffs, Buffalo was likely in a similar position; they were fortunate Ruff had history in Buffalo.
His assistants in Vancouver were questionable at best, as was the general quality of those Canucks rosters. I'm going to venture that if Ottawa's bringing him in that they're aware of his past coaching history. Think whatever you want, it's not my job to change your mind, but if Ottawa can surround him with competent, NHL level assistants I don't see why Green couldn't potentially have some success there.