Power Attack was a horrible time-waster. Good riddance.
It was a horrible time-waster on many different levels. If a player sat there and thought about their attack roll for a few seconds, no big deal. But what happened was those few extra seconds would slow down the whole game, because everyone else was taking a few extra seconds, too. It just added more of this: "Um...I do...uh...no wait. I do this...hold on..." to the game.
Also, power attack got complex and time-consuming when you factored it in with all of your buffs and boosts.
"Oo! I got Bull's Strength. We'll I'm sure to hit him now. Wait, maybe I should power attack for 2 points, channeling my extra +2 to hit into damage. Plus, I'm two-handing it so I'd add +4 points to damage."
"Don't forget, you got bless."
"That's right! Maybe I should power attack for -3 to hit."
"You also could smite evil."
"I could do that. And channel even more of my to-hit into damage. Plus I get damage from smiting."
"So what are you going to do?"
"Okay, wait. I have a question. What if I...."