(laughing) if you knew me, this is a really funny question.
No, a walk or SF doesn't negatively affect BA, but a walk isn't a negative event, it's a positive one (not making an out, getting a baserunner) and isn't accounted for in BA. Same problem with types of hits. A single is worth the exact same amount to BA as a HR, yet nobody would argue that singles are as valuable as HRs.
So OBP (On Base Percentage) and SLG (Slugging Percentage) and better measures because they do take into account things like walks, hit by pitches, and types of hits. Combine them and you get OPS (On Base Plus Slugging). Team OPS correlates much higher to Team Runs than Team BA does.
Multiply OPS with Plate Appearances and you get a simple calculation of a stat called Runs Created which approximates the amount of team runs a single player generated.
Time Raines is tied with Tony Gwynn, ahead of Killebrew, Carew, Clemente, Staub, Stargell, Banks, and Brock in Runs Created.