I believe they didn't want the players to rely too much on perks in this game. I prefer it that way to be honest. Perks should just be minor bonuses/protection.
I mostly agree, except for Toughness. Toughness is about as close as a perk can get to a necessity, without it you're more than likely screwed in any 1-on-1 firefight thanks to the absurdly exaggerated flinch introduced in BO to somehow justify ONE more perk. --- Russian is my first language, so yes there may be a spelling error or two. I <3 Jesus.