As OldGuy says, it depends on how your league scores. Also, it depends on who else is on your team. It’s possible to do very well in fantasy baseball without having any really huge stars, as long as your scoring types are well balanced. You don’t want too much of one thing and not enough of another.
In my league, for example, scores are calculated based on your league position in a variety of different stats. If you are coming first in a particular stat, you get 14 points (14 teams in the league), and if you are coming last in that stat, you get 1 point.
So, take one of Henderson’s most obvious advantages: stolen bases. If he’s the only guy on my team who can steal bases, then he could be a huge help to me. But if i have four or five other guys who can also steal bases, then Henderson’s base-stealing ability might not matter very much, because if i come first in the category, it doesn’t matter whether i win the category by 1 or by 50. If i’m leading by too much in one category, i look to trade one of those players for someone who has good stats in a category where i’m weak.
Obviously, Henderson was about far more than stolen bases, and his 1985 was certainly awesome. One area where it is a bit lacking, in Fantasy terms, is RBI. We can talk all day about whether RBI is a good stat, but the fact is that it counts in most fantasy leagues.
Another awesome year was Barry Bonds in 2001: .328/ .515/.863 with 73 HR, 129 runs, and 137 RBI. And 177 BB, which also count in some leagues, including mine (although i don’t think there’s any need to count both BB and OBP, as my commissioner insists on doing). His 2002 was about as good, although the HR total dropped a bit. A few of Bonds’ early years were awesome as well, with slightly less power, but more speed, giving him SB totals in the 40s and 50s to go along with his high average, high OBP, good SLG, and still excellent HR numbers.