The Bulls played better without Wade, with Wade and Rondo in the lineup at the same time, they need two basketballs. Both believe they're the players of 5 years ago. Hopefully team chemistry will remain elusive for the Bulls.
I tend to look at each opponent according to their backcourt lineup, and the size and toughness of the front court, when deciding if the team has the potential to give the C's trouble. In other words...match-ups.
Butler is a nightmare match-up for any team, buy especially so for the undersized Celtics, because that leaves IT, at times to deal with Rondo, and Wade. Lucky both mostly on their down side.
In the front court the Bulls are big, and tough, but not really overly skilled, they really don't have a reliable inside scorer.
I don't think this will be an easy series, but the C's should win in 6.