Irving was a flaming bag defensively last season and hasn't shown he is ready to take that end of the floor seriously. His minus-3.4 defensive RPM suggests he was one of the worst defending starting point guards in the league, hurtful enough to erase all his value on the offensive end. Though that probably is too harsh of an assessment, Irving will have to stop relying on his teammates to clean up his mistakes if the Cavs want to be a real defensive outfit. If you thought James yelled at Chalmers in Miami, just wait until he sees Irving "fight" through a screen 20 times a game.
Ranking 11th by the end of the season, the Heat weren't much better than the Cavs on defense. Adding McRoberts and Granger may provide some relief in place of Battier and Beasley, but the gains will probably be minimal. By injecting some relative youth in McRoberts and Napier, the Heat should have more energy on that end, but it's not as if McRoberts is a defensive ace.
Still, the Heat have the slight edge here. Varejao, Zeller and Thompson just aren't the rim protectors that the Cavs need with Irving in the fold. Even with Wiggins and James potentially wreaking havoc on the perimeter, it's hard to see the Cavs being good enough right away to get the nod.
This won't be an easy choice for James. On one hand, he and his family have an opportunity to return back home to Cleveland, where he still has a house nearby in Akron. On the court, the Cavs are stacked with young talent, which could be a refreshing change for James after carrying the load in the Finals against the Spurs.
But the Cavs simply aren't ready yet to contend for titles right away. If that's the priority, James should head back to Miami. I asked ESPN Insider Kevin Pelton to put together a projection for next season given the projected rosters, and the numbers backed up the conventional wisdom: The Heat would be the superior option now, with a projected record of 57-25, while the Cavs posted a projected 55-27 record. It's hard to imagine a young squad like Cleveland's would have enough discipline and maturity to reach the Finals against battle-tested teams like the Chicago Bulls and Indiana Pacers. (Note: the Cavs' projection included Zeller, who was only expected to produce about a win for the Cavs' bottom line. That could be replenished with a veteran at a minimum deal.)
In the aftermath of the Spurs' brilliant Finals performance, we're quick to dismiss the Heat's season as a total train wreck. But they posted the fourth-best point differential in the league last season and cruised into the Finals with relative ease. If a trip to the Finals is a failure, 28 other teams would kill for that failure.
Looking past next season, the Cavaliers might offer James more upside. Indeed, Pelton's projections have the Cavaliers eclipsing the Heat in 2015-16 as Wade and Bosh age, but there's way too much uncertainty a year from now to make any hard conclusions in the data. In terms of basketball talent, the smart move for James might be to re-up with the Heat for a one-year deal and then revisit his situation next summer after he has seen what Bennett, Wiggins and Irving can do under Blatt's leadership. Cavs fans would be wise to postpone the Cleveland homecoming festivities.