i think era and whip would provide enough importance for people to use relievers.
what you have to do is break down the categories.
* QS: starter stat, 100%. favors quality starters.
* Ks: favors starters, relievers contribute, bad starters don't really add much. As a point of comparison, Tim Wakefield had 117K's last year; Mariano Rivera had 77. The 30th most K's in the league last year was Brett Myers with 163. Number sixty was Galarraga with 126. The top reliever was Brad Lidge with 92 and a few guys in the 80s. So I guess I would say K's provide incentive to start decent to good starters over relievers but not a compelling one to start bad starters over good relievers.
* Ws: favors good starters, lucky starters, starters on good teams, and some lucky middle relievers.
* Sv + HD: favors relievers exclusively.
* ERA: favors relievers and top-of-the-order starters who are really valuable since they have a low ERA and their ERA counts for so much since they rack up 240 innings.
* WHIP: see ERA.
I really think if you want 6 categories, that is a good system for pitching. You have reason to play at least decent starters; #4 and #5 guys will hurt you too much in ERA and WHIP to make up for whatever additional they get you in Ks or QS (which they won't have many of). Ace starters are the most valuable since they'll be contributing in 5 categories, but that's how it should be. And your ace relievers, whether they be closer or set-up men, are at least as valuable as a #3 starter, with the ace closer beating out the ace set-up man.
Honestly, I don't see anything wrong with it. The only "strategy" is to draft good pitching. You're not going to win drafting all relievers or all starters and that's how it should be.
If I was drafting in this league, I would grab probably 3 ace starters in the first 6 rounds, 2 good closers before round 10, 2 good middle relief guys around round 15-17, and then take chances on starters and juggling those spots until I found the guy who was hot this year.
0-3 to 4-3. Worst choke in the history of baseball. Enough said.