So, lets look at the Nets roster for this year.
Aside from Center, every position is extremely deep. The starting five is as good as any in the league with Deron Williams leading from the point and Johnson and Gerald Wallace scoring from the wings. The team doesn't have a legitimate "big three" but Williams is the second best PG in the league, while Johnson is probably a tier two or three shooting guard. You know what you're going to get from Lopez and Humphries, but they both are solid players who do what they're asked of (Lopez scores, Humphries rebounds).
Deron Williams had many people thinking he was taking a hike to Dallas, but he had a change of heart and decided to sign a 5 year/98 million dollar deal. Williams had a fantastic year last season having a final stat line of 21 points and 9 dimes a game. Williams is a player who knows when he has to be selfish for the team to be successful, he frequently takes the ball to the hoop and draws quite a few fouls. Williams has two reliable backups one in the form of ex-Bull C.J. Watson. Watson put up solid numbers last year in Chicago, scoring 10 points and dishing out 4 times a game. Keep in mind the numbers are inflated due to Derrick Rose's injury last year, but Watson won't do more than spell Williams for 10-15 minutes a game. Tyshawn Taylor was a star in Kansas during their national title run, but he won't get many minutes in Brooklyn. Taylor is a developing prospect who won't see much floor time.
Joe Johnson went from the quietest star in the NBA to having one of the worst contracts in basketball history at 6 years/119 million and being labeled a bust. That doesn't mean Johnson isn't useful anymore; he's still a bulls eye shooter (39% from outside the arc in 2011-12, 19 points a game) and he also records 4 rebounds and 4 assists per. Johnson will likely be expected to be the Nets go to scorer, and with a point guard like Deron Williams getting him the rock, Johnson could explode this year. His backup, second year player Marshon Brooks, will be the sixth man this year for the Nets. Brooks is a pure scorer, puting up 13 points a game last season as a rookie; you won't get much else out of Marshon aside from points. The Nets brought in Bogans to add some veteran leadership, he will get next to zero minutes.
The Nets thought they were going to lose Gerald Wallace in free agency but managed to snatch him back with a 4 year/40 million $ deal. Wallace is a reliable scorer with 14 points a night, but more importantly he rebounds; last year he grabbed 7 boards per game. Wallace's all around ability will be extremely helpful for Brooklyn these next few years. Behind Wallace, the Nets don't have much, Jerry Stackhouse is too old to be playing in the NBA and Tornike Shengelia won't do much in his first year in the NBA.
The Nets are two guys deep at PF with Kris Humphries and Reggie Evans. Both guys are rebounding machines, but neither will put up a lot of points. Evans is a defensive bruiser down low, and Humphries is also a tower at 6'9. At center the Nets have Brook Lopez, a guy who signed a 4 year/60 million $ deal in July. Lopez will put up close to 20 points a game, but will need to get a lot better at rebounding and defensive for the contract to be justifiable. Mirza Teletovic, the Nets first round pick, is a highly touted big man out of Serbia. Nets fans are optimistic that he has a chance to be big off the bench, I disagree. Teletovic will need his first year to adjust in the NBA.
The Brooklyn Nets look good on paper, they have a star point guard, two solid wing scorers, and two big guys who can battle down low. The problems that lie with them are that they are an average defensive team, and they don't have a lot of reliable players off the bench (they traded most of them in the Joe Johnson deal.
When comparing a team like the Nets to the Celtics, I look at the experience factoid. Most of Brooklyn's players have little playoff experience and haven't made it out of the second round of the playoffs. In a seven game series against Boston I would pick the Celtics in 6 games, they're deeper, they have experience and they have a solid core that has been in Boston for the last five years. The battle between Rondo and Williams would be a duel, but in the end Rondo has more guys to pass to then Williams does. The only problem I could see is the height factor of Lopez and Humphries. The C's don't play with a traditional center, KG is the tallest guy on the floor at 6'11 while Lopez and Humprhies are both big bodies. That being said the Nets don't have much behind those two while Boston has Jeff Green, Chris Wilcox and Jared Sullinger. Depth would prevail at the end of the day.
The Nets will only get better as the years go by, and if they pick up a few solid bench options in free agency next year they could be right in the NBA title debate, but right now they aren't ready. At this point I would rank Boston, Indy, maybe New York, and Miami ahead of the Nets. I would say you can expect 45-50 wins in Brooklyn this season, with the four or five seed in the east and a second round playoff appearance. Thats as high as I'll go... for now.