I wouldn't say that the core of New Jersey is overrated based on these games especially considering that a third of that core hasn't been playing (Jefferson). I mean J-Kidd is still a top 3 point gaurd and Carter is still a big time scorer, albeit a lazy one.
The real problem with the Nets is that they ONLY have this core. With Kristic, the team was passable last year. But much like with the departure of Bonzi in Sacto, the real flaws of the team were exposed when Kristic tore his ACL. And without Jefferson, they are a disaster.