My 12 team keeper league (we keep 12 guys) just switched from a standard 5x5 to a modified 6x6.
We start: 2 C's, 1B, 2B, 3B, SS, CI, MI, 5 OFers, Util. We start 10 pitchers each week, they can be any mix we want of SP's or RP's.
The categories now are
Hitting: OBP, SLG, HR, RBI, R, SB
Pitching: ERA, WHIP, QS, IP, K/9, SV
Strategy for hitting seems pretty straight-forward - adjust my rankings to value high OBP guys instead of high avg guys, and value power hitters a bit more because of SLG%. But what about pitching? Swapping QS for W just means no chasing pitchers on good teams - will want to just draft the most talented guys.
I have never been an advocate of punting saves in a 5X5 league - you have to be top 1 or 2 in almost every other category to win - but what about in a 6x6 league where IP is one of the categories? If I don't keep or draft any closers and start 10 SP's each week, and everyone else does compete in saves, I'm virtually (if not almost completely assuredly) guaranteed of winning QS and IP. Closers are generally stonger at K/9 than starters, but if you are only starting 2-3 each week, their impact on that stat is still diminished significantly compared to who your starters are.
You could make a similar case for punting saves, but I think stat category changes are less impactful for hitting then pitching. Plus I have a bunch of solid SB guys on my keeper list, so no point in trying to upheave my whole keeper list.
This league is hyper competitive. I finished 4th last year and my team is solid. I feel like by taking a risk the first year under new scoring rules I could find an inefficiency in the system and exploit it to my advantage. Right now I plan to keep 10 hitters and 2 SP's and just draft heavy on SP's the first 8-10 rounds.