Even though I think the Pacers have upgraded slightly this off-season, I don't think it is reasonable to expect 60-plus wins again. Last season's total came against a VERY weak eastern conference (except for Detroit).
Next season, Miami will be hard to beat. Detroit will be hard to beat. Despite losing Boozer, I think Cleveland will be harder to beat. There still are a large number of Eastern teams who I don't think will be hard to beat, and I think New Jersey will be easier to beat than they were last year.
Considering everything, I think about 57 or 58 wins is a realistic expectation.