The two teams in the finals, who were the 2 best defensive teams in the league, Bos and LA, don't have bigs that are extremely athletic and play above the rim. Perkins in not explosive. Garnett hasn't been in years. Big Baby can't get off the floor. Bynum has hobbled around on an injured knee for a few seasons now. Gasol was considered very soft on that end, and has never been considered a great athlete. So the top 2 teams defensively, who made it to the finals, don't have anyone on their frontlines who will impress with their vertical jumping ability. This is one example of many.
Experience, size, positioning, rotation, understanding angles, understanding nba defensive schemes, knowing opponents preferences, and timing are all much more important than how high a given player can jump. To come out and say we should put an emphasis on playing above the rim seems incredibly rediculous to me.
When you want to have a great defensive team, or you want to make improvements on that end, do you think a coaching staff will tell the entire frontline to spend the summer working on their vert jumping? Please. They will head straight to the film room, and then practice schemes and rotations on the court.