True, and so was Jersey City, but there are certain distinctions. Hoboken (and Jersey City) are a lot closer to Manhattan. Also, Hoboken did not have close to the same level of blight and crime that Newark does now. (Newark is consistently ranked as one of the most dangerous cities in the country).
But most importantly, a stadium or an arena has never, to my knowledge, spurred the revitilization that always gets promised. So yes, Hoboken and Jersey City came back, but not because of sporting team, and their plans for revitilization did not focus on the sorts of projects that Newark has chosen.
Weber ultimately works for the Devils. His chances of success largely depend on the competence of businesses and politicians based in Newark. Is that something you would ever bet on? I certainly wouldn't.
EDIT: I guess when I was talking about accessiblity, I was thinking of my own circumstances. I liver in Manhattan now, and when I was in Jersey there was a direct line to Hoboken, so yeah, can't speak for other places. That's probably why McMullen's plan required a massive infrastructure committment to deal with parking, access by car, etc.
One thing that you're failing to look at which is that Hoboken is 2 square mile with 50,000 people whereas Newark is 24 square miles with 280,000 people. If you change one street in a mile square city you're fast on your way to changing the whole city. The Ironbound has always been deemed safe and is around twice the size of Hoboken with about the same number of people. Downtown is right next to the Ironbound and is around the same size as Hoboken but with an eighth the population. These are the areas you need to focus on, because you're not trying to draw the average Devils fan to Springfield and Irvine Turner Boulevard. Nor are you trying to get them to Roseville and Bloomfield. You're trying to get them to Downtown. If that area can improve to a certain point (which it already has come most of the way) to where people can start to view it as a destination, the improvements will be able to continue to spread little by little through to the rest of the city. After downtown I'd predict that North Broadway will be the next area that will experience heavy redevelopment and improvement. In short, while Hoboken is really only the size of a neighborhood, Newark has neighborhoods within it that are bigger than Hoboken and thus the city as a whole will take a much longer time to achieve the turnaround that Hoboken pulled off.