2004 Red Sox beat a 92 win Angel team, a 101 win MFY team, and a 105 win Cardinal team. I remember there being a discussion at the time whether that was the highest number of opposing team wins by any WS champion, but I can't remember the outcome and I can't find anything quickly on the interweb.
That Cardinal team... hard to believe they won 105 games. But then again, they had some serious bats:
Pujols: 46 hr, 123 rbi, 1.072 ops
Rolen: 34 hr, 124 rbi, 1.007 ops
Edmonds: 42 hr, 111 rbi, 1.061 ops
Sanders: 22 hr
Mabry: 13 hr, .867 ops
Walker: 11 hr, .953 ops
Their problem - which was identified at the start of the series - was that their starting pitching was solid, but not the kind of guys who had the kind of stuff to consistently get Sox' hitters out. Carpenter was terrific but after that, a bunch of #3 types. Of course, Carpenter was out for the Series with an injury and he might have made a difference.