The success of a team is based upon much more than the sum of its parts.
Great teams come together in ways that mask their deficiencies, while other teams can fall apart in ways that mask their strengths.
With that being said, guessing which teams will come together and which will fall apart is impossible to do during the offseason. Every team has different players and/or coaches than they did last season, meaning every new group has a chance to gel or repel in unpredictable ways.
Given that, the most concrete measure of a team that is currently possible is an analysis of the roster player by player.
But we don't have the time or patience for that, so the next best thing is a unit-by-unit breakdown, relative to other units around the division and conference.