A Quality At Bat means many different things. If a hitter hits 3 line drives to the SS while only seeing 3 pitches, that is 3 QABs for me.
Again, we are talking about evaluation for pro baseball. No pro scout has submitted a players after watching him hit and said "Wow...he may not be able to hit but he can sure draw a walk." Without the hit skill, the plate discipline is irrelevant.