I think if the Cavs can utilize Miami's trap defensive scheme, it'll be enough to take them to the level they need to be with or without the addition of a back up defensive C. LeBron knows that defensive scheme inside and out, and it was mostly about excessive effort and being able to recover on time to play help-side defense. Every teams have weaknesses, and the Heat defense were only good for two years. If the Cavs plays hard enough on the defensive end, the need for an interior defensive big won't really matter that much this season. The few weaknesses that Miami had were, they had the tendency to gave up open 3's and couldn't secure defensive rebounding. I think we can safely say that the Cavs will be 100x better at rebounding the ball and securing possessions than the Heat ever were in the last four years.