The "pay to win" drama just comes from the rarity of set hats and the fact that someone wearing just the weapons has a disadvantage to someone who has the hat as well. Even then, the only set hat that suffers from this is the Milk Man; every other set either has a downside or has too insignificant of an advantage to really matter. The Christmas sets don't even require the hat to have the bonus, so Valve has obviously learned from its mistake and doesn't plan on repeating it.
Crates have nothing to do with it. They're just dumb useless shit that won't go away.