There are two different questions in the OP. Which side of the ball is worse, and which side of the ball is the bigger issue. IMO the defense is worse, although not by a lot, and against ACC teams I'd argue the defense was better than the offense in 3 of the 4.
But IMO the offense is the bigger issue and the reason for that is because with the way the program is set up, the offense has to be the side of the ball to win the games for us, and the defense needs to be good enough to make sure that the decision of the game is in the hands of the offense. To me that's the only reasonable way to look at things when your headcoach is also the offensive coordinator and more so given the offense we run. IMO the defense has put every game in the hands of the offense. Even Pitt where the offense in general played better. The defense kept it a one score game and let the O have time to tie it, then got a turnover to set up the go ahead score. And at the end of the game we were tied, had the ball on offense, and the game was squarely in the hands of the offense.
So our offense may be the strength of the team, but that's almost a forgone conclusion with the way our program is set up. The issue, imo, is that our strength hasn't been strong enough lately.
To put it another way. With the way our offense has played, if the defense played up to what I hope they can reach we'd be 5-2. I don't think it's reasonable to ask a defense to cover for an offense that scores 21 and gives up 14 on turnovers. And against Clemson, well yeah. But with the way our defense has played, if the offense played up to what I hope they can reach we'd be 6-1. Miami we should have beaten, and imo would have, without the turnovers, and against Pitt we should win a tie game with 4 minutes left and the ball in the hand of our 3rd year senior starting QB.