I've seen several ideas around various forums for "fixing" power attack. Like many others, I always thought it could unbalance things at times. Though, it's also important that there are times when a few well placed swings can take an enemy out…just like in real life.
Anyway, noticed your summary of feats suggests "max -5", but the feat description seems to take a different tact….?
Also, the description speaks of "iterative" attacks, but also suggests you get only one swing while using power attack….?
Power Attack