Dupuis got a huge boost in his stats from playing with Crosby (24 points in those 22 games, compared to 35 in the other 60). He also played 22% more minutes than Higgins to put up those 31% more points (59p in 82g to 43p in 71g). Dupuis is the better offensive player of the two, but it's not as close as last year's numbers suggest.
Higgins also has a better defensive game than Dupuis. His 50:16 TkA:GvA ratio was 5th best in the league for players with 50 or more takeaways, and only narrowly behind the likes of Toews, Hossa, Oshie and Callahan. For reference, Dupuis had a ratio of 25:18 TkA:GvA, which is a bit above average, but not half as good as Higgins.
I don't fault you for taking Dupuis, I imagine the majority of people would, but it's closer than you think.