I'm guessing this is a Phenoms league given the scoring lineups. Last year I was in a 2-3 (no flex) with the same scoring, and won the league on the strength of my WRs. This year, I also drafted a league exactly like you are describing and heavily targeted WRs and sacrificed RBs given that I'll only start one.
Last year, I dominated the league because I had 3 decent RBs (Bradshaw, Tomlinson, and Mendenhall). All I needed for their production was 10-15 PPG (which I typically got), because at WR I had Calvin, Nicks, Lloyd, and M.Williams. Playing match-ups to select 3 out of these 4 each week generally produced 20 PPG each, and when they each hit, I was pretty much unbeatable. Won the high score for the regular season and the playoffs.
There were certainly teams in the league with better RBs. For example, the second place team had Foster, Hillis, and BJGE, but I outscored him by about 18 points per game (140 vs. 122).
For the team that I drafted this year in the format exactly as you described, I ended up with:
QB - Romo
RB - P.Thomas, J.Stew, CJ Spiller, Hardesty, Steven Ridley, and LaRod Stephens-Howling.
WR - Jennings, B. Marshall, B. Lloyd, Dez Bryant, SSmith Carolina, and Branch
TE - Daniels and Cook.
I know this is a bit of an absurd strategy, but given the QB-RB-4WR-TE lineup that I plan on starting + the fact that TEs and WRs get full PPR, I basically consider RBs the least important position. I sort of took this strategy to the extreme, but I felt like the risk was worth it.
Also, Don't forget to target a defense relatively early. Phenoms has some weird scoring where a good defense will put up 20 points per week, because total yards allowed are a scoring category. I'm currently in a different slow draft, and the Steelers went in the late 7th. That's crazy, but try to grab a top 6 Def, and feel free to play match-ups each week with another defense whenever an average defense is playing the Bengals/Seahawks/49ers/Jaguars etc.
