First post, longtime reader.
I think "B" is a fair grade.
My expectation is for the team to be competitive in winning the Atlantic this year, though that isn't all that impressive. Having a winning culture is important, and developing this team does matter. Obviously, the NBA is a superstar league for the most part, but that's not the only outlet for success. The Hawks are a solid example of this. The goal is to win championships, and the Hawks came up short. Some will say that this is due to lacking a superstar, but I tend to think it was more injuries.
I think a lot of people are quick to panic if we don't get a star each chance we have at one. Guys who come to mind that people think we should get are Kevin Love, DeMarcus Cousins, and most recently, Greg Monroe. While I think each of those players are talented, they do have some flaws - especially as max players. There is a very small list of players in the NBA that are worth mortgaging everything for and I don't view any of those players as one of those worth doing so for.
Yes the East is weak now, but things can change quickly. I think the expectation fans should have is that Danny fields a competitive team in the East now, and continues to put us in a position to acquire a superstar. It's fair to say that he is doing so. We are positioned well with the salary cap (granted with the cap jump this devalues the work he has done), with the draft (4 possible first rounders), and young/cheap players. The Harden situation, Melo situation, and others similar situations from the past are the types of scenarios that we will be well positioned to make a move for.
A big thing with the draft is luck - it's very hard to determine what a draft class will look like years in advance. It has been mentioned before where many of the top players were last year in that regard, and where they ended up. 2016 looks very top heavy, but we do have a chance to land there with the Nets pick, if not right outside of where we need to be. Sometimes things take a few years to develop, there are 30 other GM's and teams with the same goal as the Celtics and Danny. We are just a few years removed from being one of the top teams in the league and already were able to make the playoffs. The alternative is tanking and ending up like we did in the Pitino years, or the current Sixers.
If we had tanked two years ago, who would you have taken ahead of Smart? The only guy I would say is Wiggins, but other than that you have Parker (torn ACL - let's see how he comes back), Gordon (hasn't shown much other than an athletic defender with some explosion), Exum (nothing about him makes me think he'll be a better pro that Smart), and a guy a lot of people here wanted in Embiid (who may never play in this league).