Yes the Sweeney Plan can work (even in roto). However, there are some issues:
The idea here is to walk away with all 5 pitching stats, and lock steals, runs and batting average. The thinking is that you grab the best pitchers unchallenged while everyone is after the stud hitters. Then grab the less coveted base stealers that hit for average.
The problems are that these last few years there have been fewer base stealers that hit for high enough average to ensure you win both categories. This means that there are a few must have players, which defeats the purpose because part of the idea is that "anyone will do as long as I have enough SB guys." Also, many owners will target power-scarce positions (2B, SS) for their SB production, which may cut into your must haves. In 2014, two top SB/Avg 2Bs went in the middle rounds, which defeats the "less coveted" idea behind Sweeney.
The PEDs crackdown has caused pitchers to dominate these last few years. What this means for Sweeney is that there's less room between the elite pitchers and the rest. In other words, it's harder to "corner the market" on top SPs and guarantee winning all SP categories. Another owner that didn't focus on SPs, but still has a top staff, can still challenge.
Lastly, Saves have been fickle and annoying. Especially in 2014 (remember how the year started?). If one or two of your closers loses their job and owners get the jump on you and pick the FA clean, there goes The Sweeney Plan.
In short, it relies on certain "certainties" which aren't all that certain anymore: That...
-you assemble a powerhouse SP staff unmolested that can't possibly be challenged.
-while ppl grabbed power hitting studs, you grabbed a bunch of SB, high BA run scorers.
-your chosen closers do well, don't lose their jobs, and if someone does, you can grab a good replacement before you get beaten to the punch.
I love mock drafts.