I don't think steals are that important. Last year, I won my league of 12 while coming in second to last with 80 SB. I certainly would not give up power (which counts as HR+RBI) to be good at one category.
Saves are important. Generally, good closers will get you more K's per inning than your starters, have lower ERA, and lower WHIP. So, I suspect that when you are giving up Saves, you are also giving up other categories, as well. (Escobar might be the exception.) I just picked up Villaferte from SD based on this principle-- he's a closer that was available in my winners league. Last year, I was in much the same position as you and grabbed DeJean, the Milwaukee closer who actually did okay-- 27 Saves. If you can't find permanent closers, nab Kline or another temp closer. Sometimes, the temps turn permanent. Riveria's injury could give you save opportunities for example, and if you guess wrong on the Save opportunities, no problem, as Yankee middle relief will help WHIP, K, and ERA. My tip for next year: If there are closers left after the first 15 rounds, you can't go wrong by nabbing them one by one. (Ended up in 6th Place in Saves last year, but have learned my lesson and now covet all closers but Looper and the Cubs guy last year and currently have Foulke, Mantei, DeJean, Villaferte and Hoffman-DL.)
Why did I win my league last year? It was people like Tejada (R+HR+RBI+AVG) and Martinez (who I picked off waivers), who you just have to play every day.
BTW, this year, I have Soriano, but he just might be my only SB threat. In my league where everyone else is fighting over SB, I might come in last in SB, but first in the other offensive categories.
Another tip. I just love the K pitchers, like Santana [and I'm hoping K-Rod], who give you K, ERA, and WHIP plus an occasional W or Save without eating up all your innings.