Certainly making the most roster moves will not ensure you the league title but it should help more than hinder.
I'm in 5 roto leagues.
3 Cafe member leagues, 1 Yahoo winners and 1 Yahoo public where I'm punting the saves category for the hell of it.
In the Yahoo winners league I've made 28 moves, the most is 32 and the least is three. Everyone appears active. I'm leading the league by 20 points, the least active person is second and the most active is third.
In the Yahoo Public I've made 14 moves and am leading the league by 5 points. 7 other teams have made at least 10 roster moves, the most is 21 by a team that is in last place, 10 points behind the second last team.
In the Cafe Challenge I've made 17 roster moves and I'm leading the lead by 4.5 points. The most roster moves is Mr Marley with 23. Everyone has made at least 7 moves but interestingly the bottom five placed teams have made the least roster moves. Not sure if there is anything in that or not.
In the Cafe Members (Gene Tenace League) I've made 33 moves. Purple Haze has gone beserk with 58 moves to date and the third most is 23 moves. Next highest is 10 and the least is 2 by Curious George. The first three places are filled by those with the most roster moves. Curious George is last in the league by 9 points.
In the only league I'm not winning to date, Bleach's 16 team league, I've made 32 moves and I'm in 4th place, 12.5 points behind AKHomebrewers who is in first place and has made just 8 moves. Every team has made a move with the second, third and fourth placed teams being the most active. The fifth placed team has made only 2 roster moves and the seventh placed team just 1.
So after all that hot air I guess the moral of the story is that it pays to be more active than most in your league if you want to be a winner