Straight to the point: there are perks and weapons that are aviable to buy for real money only and some of those seem really powerfull. For example a perk that shortens the fuse on smoke and regular bombs.
I have been playing without any of those items and I have the top score most of the time, but it still bothers me. I don't remember this being a thing on the PS3 version of the game.
And you know what the worst thing is? I caught myself considering buying some of those items, even if it'll just reinforce this aweful trend.
Why, Naughty Dog, why? (Well we know the answer is "money")