Assuming that Toronto and Boston are a lock at 2 and 3 respectively. What team poses the biggest threat to the Cavs in the 4th seed as a second round matchup? Miami? Atlanta? Pacers? Maybe even an unsuspecting Detroit team in the 8th seed?
I would have to say Miami out of those teams.
Hassan Whiteside is one of the top rim protectors in the league, so Lebron and Kyrie will have have a hard time getting easy baskets in the paint. Wade can still have big nights and put a lot of pressure on an opposing defence, and JR Smith is unlikely to be able to do much against him defensively. Irving and Dragic can both have big nights offensively, and both suck defensively.
Joe Johnson is old, but he's still got the ability to pull out the odd big game - he can force Lebron to play some form of defence.
If Bosh is on the active list and somewhat healthy, then Miami could be a really tough matchup for the Cavs.
Atlanta would probably be the next hardest matchup I think.
I don't see Indiana or Detroit posing them much of a challenge.
Chicago might be a dark horse if they make the playoffs. Cavs don't really have an answer for Gasol (Kevin Love sure as hell can't defend him) and Butler could make things hard for Lebron on both ends of the court. If Chicago is lucky and Rose is healthy and has a strong series, then he could put a lot of pressure on Kyrie defensively.