Free agency.
The C's are in a very interesting position, where they are one of the top teams in the NBA, but not yet an elite team. They have great assets that, while I will acknowledge are not guarantees, could help them be a serious threat for years to come. In addition to this they have an opportunity to sign a max contract player this upcoming off season.
Ainge and Stevens have both stated that they want to build a successful team for many years to come, and I think that all begins this free agency. When you look at the situation as adding a top 4 pick this year, potentially a top free agent, next years Nets pick, and continuing to develop our young talents alongside our veterans than the future looks very bright in Boston for many years.
However, on the flip side of this, the team as currently constructed does not look like they can compete with the upper echelon of elite teams in the NBA (cue KG's "Anything is possible!"). I understand why some would want to make the big splash now, but doing so would appear to come at the expense of our future flexibility in terms of both our assets and cap space.
Personally I'm just not ready to sacrifice that future window for the names that are being thrown around, though again, I understand that some feel that is the best route to take. I believe this upcoming off season will be the true telling moment. If the C's can sign a top free agent and still hold on to those draft picks than we will have plenty of reasons to celebrate!